Add 'clean' target - suppresses this non-error:   make[1]: *** No rule to make target `clean'.  Stop.
Add 'clean' target
- suppresses this non-error:
  make[1]: *** No rule to make target `clean'.  Stop.

Change-Id: I4df21cbc45c14f37a5c11ccd4796d50f91f38aeb

tcpcloud/contrail-packages,Juniper/contrail-packages,Juniper/contrail-packages,vpramo/contrail-packages,fpytloun/contrail-packages