Fix showing help message

It wasn`t possible to print help message by
providing "--help" parameter since the script was expecting for at least
2 parameters

Change-Id: Ia67eaf259e51ba1420c77c63224636ee95f3d736
diff --git a/keystone/files/keystone_keys_rotate.sh b/keystone/files/keystone_keys_rotate.sh
index ccec5ff..344635f 100644
--- a/keystone/files/keystone_keys_rotate.sh
+++ b/keystone/files/keystone_keys_rotate.sh
@@ -9,7 +9,7 @@
 EOF
 }
 
-if [ $# -lt "2" ]; then
+if [ $# -lt "1" ]; then
   usage
   exit 1
 fi