Whitelist regexp and fmt.Errorf global vars

[korjavin]

I got some good exception from:
https://github.com/bombsimon/gochecknoglobals/tree/whitelisted-selectors

[CLAassistant]

All committers have signed the CLA.

[tpounds]

@korjavin This is a patch that deviates from the upstream repository (https://github.com/leighmcculloch/gochecknoglobals) which means it will make it harder to source directly from that in the future. I'm not sure what @jirfag's policy has been in this regard but my opinion would always be to stay in sync with upstream linters to maintain compatibility with their behavior.

[tpounds]

@korjavin One additional thought is to provide a way to configure additional whitelist rules within .golangci.yml and/or command line options. This provides more flexibility to all projects without relying on hardcoded rules within the linter. Thoughts?

[jirfag]

@korjavin thank you, but I wouldn't like to import patches not from the upstream repository. Why can't you merge it into upstream first?