Merge pull request #2260 from Carreau/fix-mpr-again

fix mpr again.

Closes  #2259.

tools/git-mpr.py

@@ -76,7 +76,7 b' def main(*args):'
             action='store_const',
             const=True ,
             help='try to merge as many PR as possible, one by one')
-    parser.add_argument('integers',
+    parser.add_argument('merge',
             type=int,
             help="The pull request numbers",
             nargs='*',