Fix tools/cleanup-images script error

When cleanup-images is launch without parameters the following error is
triggered:
./cleanup-images: line 72: break: only meaningful in a `for', `while',
or `until' loop

This patch fix it.

Change-Id: Ie8c63420a4e9b0d49a4e6be4172c8f0be912b556
Closes-Bug: #1702496

tools/cleanup-images

@@ -68,8 +68,9 @@ case "$1" in
             ;;
 
     (--)
-            shift
-            break
+            echo -e "Error: no argument passed\n"
+            usage
+            exit 0
             ;;
 
 esac