Better handling of secondary volumes size

[moul]

Some new offers have size limits, we should as often as possible create a secondary volume if not manually filled. This is the default behavior on the console for instance.

See #360 and scaleway/docker-machine-driver-scaleway#40

[ViViDboarder]

This causes issues with image builder if you have a base image > 50GB.

scaleway/image-builder#14

It would be a lot more complicated, but it would be better, if possible to detect the size of the primary image first before adding in a secondary.

Easy repro steps:

root@scw-b6f9a0:~/image-ubuntu# scw -D run --commercial-type="VC1M" 100G
INFO[0000] Server creation ...
DEBU[0000] This server needs a least 50G
DEBU[0000] curl -X POST -d "{\"name\":\"50G\",\"size\":50000000000,\"volume_type\":\"l_ssd\",\"organization\":\"<org>\"}" -H "Content-Type: application/json" -H "User-Agent: scw/v1.10.1" -H "X-Auth-Token: <token>" 'https://api.scaleway.com/volumes'
DEBU[0000] [POST]: https://api.scaleway.com/volumes
DEBU[0002] [Response]: [201]
{"volume": {"size": 50000000000, "name": "50G", "modification_date": "2017-05-23T21:44:48.188970+00:00", "organization": "<orgid>", "export_uri": null, "creation_date": "2017-05-23T21:44:48.188970+00:00", "id": "4f4badba-6bd6-41e3-9ed6-c1c6da6a081b", "volume_type": "l_ssd", "server": null}}
DEBU[0002] curl -X POST -d "{\"name\":\"100G\",\"size\":100000000000,\"volume_type\":\"l_ssd\",\"organization\":\"<org>\"}" -H "Content-Type: application/json" -H "User-Agent: scw/v1.10.1" -H "X-Auth-Token: <token>" 'https://api.scaleway.com/volumes'
DEBU[0002] [POST]: https://api.scaleway.com/volumes
DEBU[0002] [Response]: [201]
{"volume": {"size": 100000000000, "name": "100G", "modification_date": "2017-05-23T21:44:50.385905+00:00", "organization": "<orgid>", "export_uri": null, "creation_date": "2017-05-23T21:44:50.385905+00:00", "id": "426e39f7-8475-4529-8ba6-9c6bff31932e", "volume_type": "l_ssd", "server": null}}
DEBU[0002] curl -X POST -d "{\"name\":\"lonely-snyder\",\"volumes\":{\"0\":\"426e39f7-8475-4529-8ba6-9c6bff31932e\",\"1\":\"4f4badba-6bd6-41e3-9ed6-c1c6da6a081b\"},\"dynamic_ip_required\":true,\"bootscript\":null,\"organization\":\"<org>\",\"commercial_type\":\"VC1M\"}" -H "Content-Type: application/json" -H "User-Agent: scw/v1.10.1" -H "X-Auth-Token: <token>" 'https://api.scaleway.com/servers'
DEBU[0002] [POST]: https://api.scaleway.com/servers
DEBU[0003] [Response]: [201]
{"server": {"state_detail": "", "image": null, "creation_date": "2017-05-23T21:44:50.636341+00:00", "public_ip": null, "private_ip": null, "id": "b25bf8fb-e177-479b-be3e-0529285b24d9", "dynamic_ip_required": true, "modification_date": "2017-05-23T21:44:50.636341+00:00", "enable_ipv6": false, "hostname": "lonely-snyder", "state": "stopped", "bootscript": {"kernel": "http://169.254.42.24/kernel/x86_64-4.9.20-std-1/vmlinuz-4.9.20-std-1", "initrd": "http://169.254.42.24/initrd/initrd-Linux-x86_64-v3.12.4.gz", "default": true, "bootcmdargs": "LINUX_COMMON ip=:::::eth0: boot=local", "architecture": "x86_64", "title": "x86_64 4.9.20 std #1 (longterm)", "dtb": "", "organization": "11111111-1111-4111-8111-111111111111", "id": "5a1091c5-6e7b-45d3-8afc-c1246b0a9913", "public": true}, "location": null, "ipv6": null, "commercial_type": "VC1M", "tags": [], "arch": "x86_64", "extra_networks": [], "name": "lonely-snyder", "volumes": {"0": {"size": 100000000000, "name": "100G", "modification_date": "2017-05-23T21:44:51.218447+00:00", "organization": "<orgid>", "export_uri": null, "creation_date": "2017-05-23T21:44:50.385905+00:00", "id": "426e39f7-8475-4529-8ba6-9c6bff31932e", "volume_type": "l_ssd", "server": {"id": "b25bf8fb-e177-479b-be3e-0529285b24d9", "name": "lonely-snyder"}}, "1": {"size": 50000000000, "name": "50G", "modification_date": "2017-05-23T21:44:51.218465+00:00", "organization": "<orgid>", "export_uri": null, "creation_date": "2017-05-23T21:44:48.188970+00:00", "id": "4f4badba-6bd6-41e3-9ed6-c1c6da6a081b", "volume_type": "l_ssd", "server": {"id": "b25bf8fb-e177-479b-be3e-0529285b24d9", "name": "lonely-snyder"}}}, "security_group": {"id": "31d0bdfe-7e16-4327-9616-3a3dec23ab9f", "name": "Default security group"}, "organization": "<orgid>"}}
INFO[0003] Server created: b25bf8fb-e177-479b-be3e-0529285b24d9
DEBU[0003] PublicDNS b25bf8fb-e177-479b-be3e-0529285b24d9.pub.cloud.scaleway.com
DEBU[0003] PrivateDNS b25bf8fb-e177-479b-be3e-0529285b24d9.priv.cloud.scaleway.com
INFO[0003] Server start requested ...
DEBU[0003] curl -X POST -d "{\"action\":\"poweron\"}" -H "Content-Type: application/json" -H "User-Agent: scw/v1.10.1" -H "X-Auth-Token: <token>" 'https://api.scaleway.com/servers/b25bf8fb-e177-479b-be3e-0529285b24d9/action'
DEBU[0003] [POST]: https://api.scaleway.com/servers/b25bf8fb-e177-479b-be3e-0529285b24d9/action
DEBU[0003] [Response]: [400]
{"message": "The total volume size of VC1M instances must be between 51GB and 100GB", "type": "invalid_request_error"}
DEBU[0003] StatusCode: 400, Type: invalid_request_error, APIMessage: The total volume size of VC1M instances must be between 51GB and 100GB
FATA[0003] cannot execute 'run': failed to start server b25bf8fb-e177-479b-be3e-0529285b24d9: StatusCode: 400, Type: invalid_request_error, APIMessage: The total volume size of VC1M instances must be between 51GB and 100GB