Push language override down into the cmd wrapper
Push language override down into the cmd wrapper

There are more things that break if we run git with i18n on. Make sure
that we always set LANG and LANGUAGE to C so that we get predictable
output.

Change-Id: I1bf1124f0b09d6658a7b0703e3b9e74ed80f4eea

entropia1/git-review,ka2m/git-review,openstack-infra/git-review