Fix call to the compile_ovn function from Devstack

It was accepting 3 arguments where first one was "build_modules".
It wasn't used anywhere in that function so it was removed from
it.
This patch reflects that Devstack change in the Neutron's functional
tests script too.

Closes-Bug: #1957887

Depends-On: https://review.opendev.org/c/openstack/devstack/+/822717
Change-Id: Id8302bf23f48b227d05f1ec2a7136935b7b1c2fb

tools/configure_for_func_testing.sh

@@ -117,7 +117,7 @@ function _install_base_deps {
         compile_ovs False /usr /var
         if [[ "$INSTALL_OVN" == "True" ]]; then
             echo_summary "OVN_BRANCH: ${OVN_BRANCH}"
-            compile_ovn False /usr /var
+            compile_ovn /usr /var
         fi
     else
         PACKAGES=$(get_packages general,neutron,q-agt,q-l3,openvswitch)