CORD-389 Fix for Accton 6712 deployment

Related to this topic:
- Disable the meter collector since right now it is not supported
- Implement extension VLAN ID selector/treatment for OFDPA
    Since it requires two special flow entries to match untagged packets
        0x1ffe/no mask (filtering rule, need to go first)
        0x0000/0x1fff setvid 0x0ffe (assignment rule, need to go second)
- Not able to point /32 IP address to ECMP group. Use /31 instead.

In addition:
- Implement serializer for ExtensionCriterion

Change-Id: I621b3ad14014d7e6945c014cdae4f7cd2939288e
diff --git a/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java b/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
index 0c26b89..4259f5d 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
@@ -615,9 +615,9 @@
      *
      * @param extensionSelector extension selector
      * @param deviceId device ID
-     * @return match criterion
+     * @return match extension criterion
      */
-    public static Criterion extension(ExtensionSelector extensionSelector,
+    public static ExtensionCriterion extension(ExtensionSelector extensionSelector,
                                       DeviceId deviceId) {
         return new ExtensionCriterion(extensionSelector, deviceId);
     }