Add logic to download the paygen_au_suite for a particular channel.

BUG=chromium:266675
TEST=Ran the main and tested with gilad's upload

Change-Id: I70ebfe537b2aa3de7d4b5655b10255ca4066711f
Reviewed-on: https://gerrit.chromium.org/gerrit/64416
Commit-Queue: Chris Sosa <sosa@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Chris Sosa <sosa@chromium.org>
diff --git a/artifact_info.py b/artifact_info.py
index 8062251..f9ba605 100644
--- a/artifact_info.py
+++ b/artifact_info.py
@@ -39,8 +39,9 @@
 # AU Suite - The control files for the autotest autoupdate suite.
 AU_SUITE = 'au_suite'
 
-# AU Suite - The control files for the autotest autoupdate suite.
-PAYGEN_AU_SUITE = 'paygen_au_suite'
+# AU Suite - The control files for the paygen autoupdate suite (depends
+# on channel defined in devserver_constants).
+PAYGEN_AU_SUITE_TEMPLATE = 'paygen_au_%(channel)s_suite'
 
 #### Miscellaneous artifacts. ####