tasks: providers: Rename 'ovs' configuration file

The tasks/main.yml is looking for "{{ neutron_plugin_type.split('.')[-1]
}}_config.yml" file. So if neutron_plugin_type is ml2.ovs, the filename
should be ovs_config.yml. This fixes the problem.

Change-Id: Ia239360dc88be48e06faf18ec7af852a91f427c7

tasks/providers/ovs_config.yml

@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This file is responsible for the L3 configuration
 - name: Setup External Network Provider Bridge
   openvswitch_bridge:
     bridge: "{{ neutron_provider_networks.network_mappings.split(':')[1] }}"