Fix installation with OVN backend and compilation

This patch fixes several issues related to the installation with
OVN backend with the OVS/OVN compilation enabled.

The OVS/OVN local directories prefix, when both services are compiled,
is now "/usr/local".

The "ovn_agent._run_process" function is calling "ovs-appctl" to
configure the logging settings of several services. Instead of
using the service name, the ctl socket file is used instead. That
is more robust and does not fail in systems with previous
installations.

Closes-Bug: #1960514

Change-Id: I69de5333393957593db6e05495f0c3c758efefdf
diff --git a/lib/neutron_plugins/ovn_agent b/lib/neutron_plugins/ovn_agent
index 09b28b6..927896b 100644
--- a/lib/neutron_plugins/ovn_agent
+++ b/lib/neutron_plugins/ovn_agent
@@ -253,7 +253,12 @@
 
     local testcmd="test -e $OVS_RUNDIR/$service.pid"
     test_with_retry "$testcmd" "$service did not start" $SERVICE_TIMEOUT 1
-    sudo ovs-appctl -t $service vlog/set console:off syslog:info file:info
+    local service_ctl_file
+    service_ctl_file=$(ls $OVS_RUNDIR | grep $service | grep ctl)
+    if [ -z "$service_ctl_file" ]; then
+        die $LINENO "ctl file for service $service is not present."
+    fi
+    sudo ovs-appctl -t $OVS_RUNDIR/$service_ctl_file vlog/set console:off syslog:info file:info
 }
 
 function clone_repository {