ovn-openstack.rst: Fix typo.
The text here was inconsistent: it referred to port 4 in the text just
above but the example used port 5 in one place.  This fixes the issue.
Acked-by: Andy Zhou
@@ -923,7 +923,7 @@ important part is::
which means that the packet is ultimately being output to OpenFlow
port 4. That's port ``b``, which you can confirm with::
- $ sudo ovs-vsctl find interface ofport=5
+ $ sudo ovs-vsctl find interface ofport=4
_uuid : 840a5aca-ea8d-4c16-a11b-a94e0f408091
admin_state : up
bfd : {}
