Add a custom SVNPoller implementation that adds " (CQ)" to author name for

masters/master.chromium.fyi/master.cfg

Index: masters/master.chromium.fyi/master.cfg
===================================================================
--- masters/master.chromium.fyi/master.cfg	(revision 119272)
+++ masters/master.chromium.fyi/master.cfg	(working copy)
@@ -3,7 +3,6 @@
 # found in the LICENSE file.
 
 from buildbot import locks
-from buildbot.changes import svnpoller
 from buildbot.scheduler import Dependent
 from buildbot.scheduler import Nightly
 from buildbot.scheduler import Periodic
@@ -17,6 +16,7 @@
 from master import master_config
 from master import master_utils
 from master import slaves_list
+from master import svnpoller
 
 from master.factory import chromeos_factory
 from master.factory import chromium_factory