CQ: handle more HTTP-related errors

commit-queue/pending_manager.py

Index: commit-queue/pending_manager.py
===================================================================
--- commit-queue/pending_manager.py	(revision 228497)
+++ commit-queue/pending_manager.py	(working copy)
@@ -218,8 +218,17 @@
     """Returns the list of issue number for reviews on Rietveld with their last
     patchset with commit+ flag set.
     """
-    return self.context.rietveld.get_pending_issues()
+    try:
+      return self.context.rietveld.get_pending_issues()
+    except urllib2.URLError as e:
+      if 'timed out' in e.reason:
+        # Handle timeouts gracefully. Log them and pretend there are no
+        # pending issues. We'll retry on the next iteration.
+        logging.warn('request to fetch pending issues timed out: %s' % e)
+        return []
 
+      raise
+
   def process_new_pending_commit(self):
     """Starts verification on newly found pending commits."""
     expected = set(i.name for i in self.all_verifiers)