Fix crash on displaying renamed file
Fix crash on displaying renamed file

A logic error in the method to pretty-print file renames could cause
a crash.  Ensure that we don't overrun the length of either the
old or new path when comparing.

Change-Id: I7f1006ec6cbdb723e77cb62b64414a960af04113

aspiers/gertty,stackforge/gertty,openstack/gertty