Fix tools/configure_for_func_testing.sh
Fix tools/configure_for_func_testing.sh

Remove an erroneous "source", we test for existing of a file, the source
is misplaced.

The source results in errors executing like:
/home/zuul/src/opendev.org/openstack/neutron/tools/configure_for_func_testing.sh: line 81: [: source: binary operator expected

Change-Id: Iea8121eb4b25e66e2527feb5bf3f8f351114c721

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