Grab complete version information from git

This is a follow up to PR #1056 which introduced the more complete version field from git.

In this PR I'm populating more git fields using Go's ldflags.

They're still not fully reported in -version, that will follow up in an upcoming commit.

I'm also not yet pushing gitMajor and gitMinor from git, that will also follow. (We need annotated tags for that to work though...)

I also made sure to fix the `release/build-release.sh` script to make sure I won't break Jenkins again since it expects the client (built locally with hack/build.sh) and the server (built from that release script) to have exactly matching versions...

Cheers,
Filipe