Increase io timeout of traffic annotation tests.

IO time out of network traffic annotation tests on the FYI bot is
increased. One of the tests takes a considerably long time to make an
output and needs to stay alive to do so.

Bug: 690323
Change-Id: Iae8384aaea46d48ad9d584b8747d1a576cec9fe1
Reviewed-on: https://chromium-review.googlesource.com/1042287
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555981}

testing/buildbot/test_suites.pyl

@@ -336,6 +336,7 @@
   'test_traffic_annotation_auditor_script': {
     'test_traffic_annotation_auditor': {
       'hard_timeout': 14400,
+      'io_timeout': 14400,
       'script': 'test_traffic_annotation_auditor.py',
     },
   },