HA flag incorrectly set for instance-ip in LBAAS

Instance-ip should be set with active-standby flag. But because of a
change in neutron plugin to set the max-instances to 2 ha-flag was
overwritten to active-active. Removed the code dependency for ha-flag
on max-instances if ha-mode is specified.

Change-Id: I7a0970a6559a062cd13651416658c982bf7554b7
Closes-Bug: #1380763