git.getref: use python-git
Fixes a "warning: refname is ambiguous." problem:
$ git clone https://gitlab.com/joshua.tee/wx.git $ cd wx $ git rev-parse 55699 warning: refname '55699' is ambiguous.
Fixes a "warning: refname is ambiguous." problem:
$ git clone https://gitlab.com/joshua.tee/wx.git $ cd wx $ git rev-parse 55699 warning: refname '55699' is ambiguous.