Added "drivers" to cells that defined ONOS_APPS.

Change-Id: I8e7cbea037ea09504662fb17ef328b547d21050a
diff --git a/tools/test/cells/beast-5 b/tools/test/cells/beast-5
index 4734281..8e959c5 100644
--- a/tools/test/cells/beast-5
+++ b/tools/test/cells/beast-5
@@ -13,4 +13,4 @@
 export OC4=10.254.1.204
 export OC5=10.254.1.205
 
-export ONOS_APPS=null,intentperf
+export ONOS_APPS="drivers,null,intentperf"