configure_for_func_testing.sh: Source lib/neutron as well
configure_for_func_testing.sh: Source lib/neutron as well

Also, set ENABLED_SERIVICES before sourcing devstack files
because they uses it.  This is a preparation for an upcoming
change in devstack. [1]

[1] I3ff136fc8330c92007cdfe91b77d7f9865eabd8d

Change-Id: Ida1f83b6b3ef9b76be13c063c7e35a8703214078

mahak/neutron,openstack/neutron,noironetworks/neutron,huntxu/neutron,openstack/neutron,noironetworks/neutron,openstack/neutron,mahak/neutron,eayunstack/neutron,huntxu/neutron,mahak/neutron,eayunstack/neutron