ctdb-scripts: Fix a bug in counter checking

If there are insufficient arguments then they can't be shifted.

This function will be removed shortly.  However, it needs to work for
now as tests will be added that depend on it to work.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

ctdb/config/functions

@@ -769,7 +769,11 @@ ctdb_check_counter () {
     _msg="${1:-error}"  # "error"  - anything else is silent on fail
     _op="${2:--ge}"  # an integer operator supported by test
     _limit="${3:-${service_fail_limit}}"
-    shift 3
+    if [ $# -le 3 ] ; then
+	    shift $#
+    else
+	    shift 3
+    fi
 
     _size=$(ctdb_counter_get "$1")