apply_issue: 89 ret code on network/Rietveld failures.

This would allow bot_update to differentiate between patch download and
aplication failures.

R=phajdan.jr@chromium.org,sergiyb@chromium.org
BUG=537417

Review URL: https://codereview.chromium.org/1380093003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@296983 0039d316-1c4b-4281-b951-d872f2087c98

apply_issue.py

@@ -209,7 +209,9 @@ def main():
           'Try visiting %s/%d') % (
               issue_to_apply, patchset_to_apply,
               options.server, issue_to_apply)
-      return 1
+      # Special code for bot_update to indicate that cause is network or
+      # Rietveld. Not 2, because 2 is returned on arg parsing failure.
+      return 3
     if options.whitelist:
       patchset.patches = [patch for patch in patchset.patches
                           if patch.filename in options.whitelist]