Bump Gerrit fetch retry logic to 6 tries and 12s initial sleep

Upon Gerrit team's suggestion, up the retry time and number of retries
to handle increased replication delay.

Bug:b/285164390
Change-Id: If833ae9bb0f8c276b761970a8b5f96ec217d11b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4621268
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Auto-Submit: Gavin Mak <gavinmak@google.com>

gerrit_util.py

@@ -44,10 +44,11 @@ else:
   from io import StringIO
 
 LOGGER = logging.getLogger()
-# With a starting sleep time of 10.0 seconds, x <= [1.8-2.2]x backoff, and five
-# total tries, the sleep time between the first and last tries will be ~7 min.
-TRY_LIMIT = 5
-SLEEP_TIME = 10.0
+# With a starting sleep time of 12.0 seconds, x <= [1.8-2.2]x backoff, and six
+# total tries, the sleep time between the first and last tries will be ~6 min
+# (excluding time for each try).
+TRY_LIMIT = 6
+SLEEP_TIME = 12.0
 MAX_BACKOFF = 2.2
 MIN_BACKOFF = 1.8
 

tests/gerrit_util_test.py

@@ -390,7 +390,7 @@ class GerritUtilTest(unittest.TestCase):
 
     self.assertEqual('content✔', gerrit_util.ReadHttpResponse(conn).getvalue())
     self.assertEqual(2, len(conn.request.mock_calls))
-    gerrit_util.time_sleep.assert_called_once_with(10.0)
+    gerrit_util.time_sleep.assert_called_once_with(12.0)
 
   def testReadHttpResponse_TimeoutAndSuccess(self):
     conn = mock.Mock(req_params={'uri': 'uri', 'method': 'method'})
@@ -401,7 +401,7 @@ class GerritUtilTest(unittest.TestCase):
 
     self.assertEqual('content✔', gerrit_util.ReadHttpResponse(conn).getvalue())
     self.assertEqual(2, len(conn.request.mock_calls))
-    gerrit_util.time_sleep.assert_called_once_with(10.0)
+    gerrit_util.time_sleep.assert_called_once_with(12.0)
 
   def testReadHttpResponse_Expected404(self):
     conn = mock.Mock()