ONOS-5270 Tunnel needs more specific states.

Change-Id: I18ddc67d55add27c970385a9048daff97f00d902
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/tunnel/Tunnel.java b/incubator/api/src/main/java/org/onosproject/incubator/net/tunnel/Tunnel.java
index ae9d92f..3f6572f 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/tunnel/Tunnel.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/tunnel/Tunnel.java
@@ -92,7 +92,17 @@
         /**
          * Signifies that the tunnel's state is unreliable and should be setup again.
          */
-        UNSTABLE
+        UNSTABLE,
+
+        /**
+         * Signifies that a tunnel is being established.
+         */
+        ESTABLISHING,
+
+        /**
+         * Signifies that a tunnel is being removed.
+         */
+        REMOVING
     }
 
     /**