git-cl-issue: respect --gerrit/--rietveld with integer argument

Bug: 736816
Change-Id: I56d222a3aad684f51c8c47f302c8a298b7a0469a
Reviewed-on: https://chromium-review.googlesource.com/549060
Commit-Queue: Aaron Gable <agable@chromium.org>
Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

git_cl.py

@@ -1056,9 +1056,10 @@ def ParseIssueNumberArgument(arg, codereview=None):
   fail_result = _ParsedIssueNumberArgument()
 
   if arg.isdigit():
-    return _ParsedIssueNumberArgument(issue=int(arg))
+    return _ParsedIssueNumberArgument(issue=int(arg), codereview=codereview)
   if not arg.startswith('http'):
     return fail_result
+
   url = gclient_utils.UpgradeToHttps(arg)
   try:
     parsed_url = urlparse.urlparse(url)