Clean up local variable usage - git functions

Cleans up the git-related functions in functions-common

Change-Id: I5f1851c0473e92c61b1e8af60e7ef32c3019f719
Merge "Clean up local variable usage - git functions"
Merge commit 'refs/changes/83/86083/2' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch
Merge commit 'refs/changes/80/110280/1' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch