Standard git user.name and user.email if not set

Git user.name and user.email will now be set to the standard values

  - Gogs
  - gogitservice@gmail.com

if user.name is not set or empty.

If user.name is set and user.email not, it will leave it this way.
Merge pull request #441 from tstorch/git-setup

Standard git user.name and user.email if not set