Weird behavior when http_proxy or https_proxy env vars specified

[ahmetb]

inspect command works fine, but when I specify a Man-in-the-middle proxy through standard env vars, it shows nothing, but doesn't fail either:

$ http_proxy=:8080 kni inspect --service hello
Resources in hello

Namespace  Name  Kind  Ready  Reason

0 resources

$ https_proxy=:8080 kni inspect --service hello
Resources in hello

Namespace  Name  Kind  Ready  Reason

0 resources

kni inspect --service hello
Resources in hello

Namespace  Name                                 Kind                         Ready    Reason
default    hello                                Service                      True
default    hello                                  ├─ Configuration           True
default    hello-tjxhq-2                          │ ├─ Revision              True
...