Simplifying error messages for regex validations.

[navaneethyv]

When there is a data validation error due to regex validation, the below format will be seen.

cfg> set instance ip2vrf protocol isis system-id aadd.tttt.srtc
CLI syntax error: "set instance ip2vrf protocol isis system-id aadd.tttt.srtc": regexp match fail: aadd.tttt.srtc does not match ^[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}

The regexes may them selves be complicated. This serves a good purpose to the developer, but from a usability point of view a simpler.

CLI syntax error: "set instance ip2vrf protocol isis system-id aadd.tttt.srtc": aadd.tttt.srtc  is Invalid input for <leaf name> .

[olofhagsand]

Implemented