[OVN] Fix devstack module for OpenSuse

The default path for the OVS tools is /usr/local/bin [0] but, by default
this location is not included in the $PATH for some distros (e.g
OpenSuse).

This patch includes the $OVS_BINDIR to the $PATH variable for deploying
DevStack.

[0]
0fc38297ba/python/ovs/dirs.py (L23)

Change-Id: If7d68212cadb8eb8a12fa3271023c9e86b2d411e
Signed-off-by: Lucas Alvares Gomes <lucasagomes@gmail.com>

devstack/lib/ovn_agent

@@ -478,6 +478,10 @@ function install_ovn {
         compile_ovn $OVN_BUILD_MODULES
     fi
 
+    # Ensure that the OVS commands are accessible in the PATH
+    OVS_BINDIR=${OVS_BINDIR:-/usr/local/bin}
+    export PATH=$OVS_BINDIR:$PATH
+
     sudo mkdir -p $OVS_RUNDIR
     sudo chown $(whoami) $OVS_RUNDIR
     sudo mkdir -p $OVS_PREFIX/var/log/openvswitch