Added deleting load balancers in the cleanup.py

Deleting the LBs via openstacksdk lib, but in case
the LB is in some transition PENDING_* state, doing
the deletion with the "force" flag implemented in
MOS Octavia.
This force option is not implemented in the current
upstream openstacksdk lib, so doing the raw request.

Related-PROD: PROD-37187
Change-Id: I2cb5781c5a291dea98f6d686cdd4f104219781dd
1 file changed