POST l7rule API call and PUT pool API call had a bug that might have
kept a load balancer in provisioning_status when the call was rejected
by the provider.
The code didn't use the right locked DB session to set the statuses and
then to rollback them when an exception was caught.
Story 2010210
Task 45947
Change-Id: I494ea357afc072360765d7a30a9488e08bfda52c
(cherry picked from commit fdcea400c6)
(cherry picked from commit 3e6f180b77)
(cherry picked from commit 81cb9d5efc)
173f024b59