Make configure_for_func_testing compatible with e.g. Centos
Make configure_for_func_testing compatible with e.g. Centos

In the configure_for_func_testing script openvswitch is installed
from source. We need to set proper flag (Q_BUILD_OVS_FROM_GIT) which
is used in Devstack to tell Devstack to install it from source and
not from packages.

This patch also removes flag BUILD_OVS_FROM_SOURCE from the
configure_for_func_testing file as it was only used in that file
and was actually duplicating the Q_BUILD_OVS_FROM_GIT option used also
in Devstack.

Change-Id: I09c79d0e9700cc2bfdf71e5314ea660de75ac1d3

openstack/neutron,openstack/neutron,mahak/neutron,openstack/neutron,mahak/neutron,mahak/neutron