<ApplicationContainer> bug 919619 move git gc later in tidy process.

https://bugzilla.redhat.com/show_bug.cgi?id=919619  tidy - node execution failure

It appeared rhc tidy was aborting because git cleanup performs writes which
may fail when the gear is out of space. The fix is to do this after other
non-write operations which are likely to free up space first.
Merge pull request #1704 from sosiouxme/bz919619

Merged by openshift-bot