Retry reservation commit and rollback on deadlock

Reservations can deadlock when concurrent commits are run from
multiple hosts on the same project. This fixes the issue by using
our convienient retry on deadlock feature.

Change-Id: I31d74f4267eaa33e798de926069d1a0f63006a59
Closes-bug: #1274341
(cherry picked from commit 9c556d1557a7056d6056b25d3b91ff4abcb97971)
Merge "Retry reservation commit and rollback on deadlock" into stable/havana