Minor fix P4 tutorial exercise 2

Change-Id: Ia97c3c2fd79ab34906e5beb34d0549d72d1216af
diff --git a/apps/p4-tutorial/exercise-2.md b/apps/p4-tutorial/exercise-2.md
index 401079e..5ab33c5 100644
--- a/apps/p4-tutorial/exercise-2.md
+++ b/apps/p4-tutorial/exercise-2.md
@@ -143,7 +143,7 @@
 
         ```
         $ cd $ONOS_ROOT
-        $ ONOS_APPS=proxyarp,hostprovider,lldpprovider,drivers.bmv2,p4tutorial.pipeconf,p4tutorial.pipeconf ok clean
+        $ ONOS_APPS=proxyarp,hostprovider,lldpprovider,drivers.bmv2,p4tutorial.pipeconf,p4tutorial.mytunnel ok clean
         ```
 
     3. **Check that all apps have been activated successfully**: