OTWO-2738 Bump up git version to 1.8.2 and fix nothing_to_commit check

With the updated Git client the status message pattern has changed
from 'nothing to commit *' to 'nothing to commit, *'.
So this fix will make our library to work across the older and newer versions.
Merge pull request #6 from nnsathish/master

OTWO-2738 Bump up git version to 1.8.2 and fix nothing_to_commit check