Update cell related util scripts to support larger cluster [ONOS-467]

Change-Id: Ie182397b7da92212cdaf6e1622b1482408b6de59
diff --git a/tools/test/bin/onos-group b/tools/test/bin/onos-group
index 0e6b396..150f947 100755
--- a/tools/test/bin/onos-group
+++ b/tools/test/bin/onos-group
@@ -49,7 +49,7 @@
 # early sanity check for instances/arguments
 [ -z "$1" ] && usage && exit 0
 
-OCIS=( $(env | sed -ne 's:OC[0-9]=\(.*\):\1 :g p' | sort -k1) )
+OCIS=( $(env | sed -ne 's:OC[0-9]\{1,\}=\(.*\):\1 :g p' | sort -k1) )
 if [ -z "$OCIS" ]; then
   printf "no controller instances, quitting early" >&2 && exit 0
 fi