Fix deprecated opt in haproxy driver

If Neutron was updated from Havana, lbaas config file defines user_group
and loadbalancer_state_path in default section but since Icehouse these
settings were moved to haproxy section.
This patch adds DEFAULT group to DeprecatedOpt.

Conflicts:
	neutron/services/loadbalancer/drivers/haproxy/namespace_driver.py

Change-Id: Ic92d4bc81ff6a3b16799414d17ac52e7a4801796
Closes-bug: #1349767
(cherry picked from commit cd3f4f7d24c92475ca698906c57f60375861b83f)
Merge "Fix deprecated opt in haproxy driver" into stable/icehouse