Second attempt to work around App Engine flakiness by retrying upon URLError

("Connection timed out"). This allowed me to successfully upload a CL I had
been stuck on for a couple of hours.

Manually tested by raising both HTTPError and URLError within this code block
and ensuring both are caught correctly.

BUG=none
TEST=none


Review URL: http://codereview.chromium.org/6304006

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@71702 0039d316-1c4b-4281-b951-d872f2087c98

third_party/upload.py

@@ -416,6 +416,14 @@ class AbstractRpcServer(object):
             url = e.info()["location"]
           else:
             raise
+        except urllib2.URLError, e:
+          reason = getattr(e, 'reason', None)
+          if isinstance(reason, str) and reason.find("110") != -1:
+            # Connection timeout error.
+            if tries <= 3:
+              # Try again.
+              continue
+          raise
     finally:
       socket.setdefaulttimeout(old_timeout)