When load balancer is deleted the corresponding DB entry is marked
as DELETED and is never actually removed along with a VIP
associated whit this load balancer.
This adds a new method to db_cleanup routine that scans the DB for
load balancers with DELETED provisioning_status and deletes them
from db if they are older than load_balancer_expiry_age. Corresponding
VIP entries are deleted in cascade.
Added new config option `load_balancer_expiry_age` to the `house_keeping`
config section.
Also changed the default value of exp_age argument to
CONF.house_keeping.amphora_expiry_age in check_amphora_expiry_age
method.
DocImpact
Closes-Bug #1573725
Change-Id: I4f99d38f44f218ac55a76ef062ed9ea401c0a02d
d73df70d85