fix(remote): improve version check
fix(remote): improve version check

Make version check much more readable, and fix it at
the same time. The previous implementation would assume
progress is supported just by looking at the patch-level
for instance.

A quick check of the git sources seems to indicate the
--progress flag exists in v1.7 of the git command-line
already.

Fixes #449

jeblair/GitPython,gitpython-developers/GitPython,breavo/GitPython,nvie/GitPython,gitpython-developers/gitpython,expobrain/GitPython,gitpython-developers/GitPython,expobrain/GitPython,breavo/GitPython,jeblair/GitPython,gitpython-developers/gitpython,nvie/GitPython