Strip trailing / or \ when rolling.

Otherwise it makes CL description like foo/bar// which is ugly.

R=vadimsh@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1468183002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@297670 0039d316-1c4b-4281-b951-d872f2087c98

roll_dep.py

@@ -202,7 +202,7 @@ def main():
   try:
     roll(
         os.getcwd(),
-        args.dep_path,
+        args.dep_path.rstrip('/').rstrip('\\'),
         args.roll_to,
         args.key,
         reviewers,