Added "drivers" to cells that defined ONOS_APPS.

Change-Id: I8e7cbea037ea09504662fb17ef328b547d21050a
diff --git a/tools/test/cells/triple b/tools/test/cells/triple
index 5a929f9..4247122 100644
--- a/tools/test/cells/triple
+++ b/tools/test/cells/triple
@@ -6,4 +6,4 @@
 export OC3="192.168.56.104"
 export OCN="192.168.56.103"
 
-export ONOS_APPS="openflow,fwd,proxyarp,mobility"
+export ONOS_APPS="drivers,openflow,fwd,proxyarp,mobility"