bridge: Use correct (legacy) role names in database.

The vswitchd database schema requires role names to be "master" or
"slave", but this code tried to use "primary" and "secondary".

Signed-off-by: Ben Pfaff <blp@ovn.org>
Reported-at: openvswitch/ovs-issues#218
Tested-at: openvswitch/ovs-issues#218 (comment)
Fixes: 807152a ("Use primary/secondary, not master/slave, as names for OpenFlow roles.")

vswitchd/bridge.c

@@ -3019,9 +3019,9 @@ ofp12_controller_role_to_str(enum ofp12_controller_role role)
     case OFPCR12_ROLE_EQUAL:
         return "other";
     case OFPCR12_ROLE_PRIMARY:
-        return "primary";
+        return "master";
     case OFPCR12_ROLE_SECONDARY:
-        return "secondary";
+        return "slave";
     case OFPCR12_ROLE_NOCHANGE:
     default:
         return NULL;