catch failure to push to remote in git-lb-push

This closes LBCORE-1417

• Temporary local branches get deleted after insuccessful push
• This adds a -k option to git lb-push to override cleanup (even for successful push)
• Slightly more printout

(not tested, comments appreciated)

added 1 commit

• 5fc67c82 - flip git-lb-push --keep-temp-branch opts logic

Compare with previous version

resolved all discussions

changed milestone to %v9r1p9

mentioned in commit 86eaf622

merged