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/devserver_constants.py b/devserver_constants.py
index dc763f1..0fe0ee4 100644
--- a/devserver_constants.py
+++ b/devserver_constants.py
@@ -6,6 +6,7 @@
 
 #### Google Storage locations and names. ####
 # TODO (joyc) move the google storage filenames of artfacts here
+CHANNELS = 'canary', 'dev', 'beta', 'stable'
 GS_IMAGE_DIR = 'gs://chromeos-image-archive'
 GS_LATEST_MASTER = GS_IMAGE_DIR + '/%(board)s-%(suffix)s/LATEST-master'
 IMAGE_DIR = '%(board)s-%(suffix)s/%(version)s'
@@ -21,4 +22,4 @@
 IMAGE_FILE = "chromiumos_image.bin"
 BASE_IMAGE_FILE = 'chromiumos_base_image.bin'
 TEST_IMAGE_FILE = 'chromiumos_test_image.bin'
-RECOVERY_IMAGE_FILE = 'recovery_image.bin'
+RECOVERY_IMAGE_FILE = 'recovery_image.bin'
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