Order mechanism_drivers list

The list of networking mechanism driver entrypoints should be ordered
to ensure sriovnicswitch is listed first, followed by opendaylight.

Change-Id: I05fdfceef13d3051d2bac5bfd624b52b2606778d
Closes-Bug: PROD-20883
diff --git a/README.rst b/README.rst
index e659bde..5712e7d 100644
--- a/README.rst
+++ b/README.rst
@@ -747,6 +747,10 @@
               driver: openvswitch
             sriov:
               driver: sriovnicswitch
+              # Driver w/ highest number will be placed ahead in the list (default is 0).
+              # It's recommended for SR-IOV driver to set an order >0 to get it
+              # before (for example) the opendaylight one.
+              order: 9
 
     neutron:
       compute:
@@ -911,6 +915,7 @@
         mechanism:
           ovs:
             driver: opendaylight_v2
+            order: 1
 
 Network/Gateway node: