Set default artifacts for download and wait_for_status calls

download and wait_for_status used to have hard-coded value of artifacts. This
behavior was changed in CL:
https://gerrit.chromium.org/gerrit/#/c/64310
This change breaks lab until this CL in autotest is checked in:
https://gerrit.chromium.org/gerrit/#/c/64706
To make the TOT of devserver work with autotest in prod, this CL is created as
a temporary fix. After CL 64706 is merged and pushed to prod, this CL can be
reverted.

BUG=chromium:269197
TEST=tested with following links:
http://dshi.mtv:8094/download?archive_url=gs://chromeos-image-archive/lumpy-release/R30-4408.0.0/
http://dshi.mtv:8094/wait_for_status?archive_url=gs://chromeos-image-archive/lumpy-release/R30-4408.0.0/

Change-Id: Id884e16f4f168a608bbc24d10131c7934e35879d
Reviewed-on: https://gerrit.chromium.org/gerrit/64884
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
diff --git a/devserver.py b/devserver.py
index e176699..852a001 100755
--- a/devserver.py
+++ b/devserver.py
@@ -411,7 +411,7 @@
     """
     async = kwargs.get('async', False)
     return self.stage(archive_url=kwargs.get('archive_url'),
-                      artifacts=kwargs.get('artifacts'),
+                      artifacts='full_payload,test_suites,stateful',
                       async=async)
 
   @cherrypy.expose
@@ -554,8 +554,10 @@
       http://myhost/wait_for_status?archive_url=gs://chromeos-image-archive/
       x86-generic/R17-1208.0.0-a1-b338
     """
+    async = kwargs.get('async', False)
     return self.stage(archive_url=kwargs.get('archive_url'),
-                      artifacts=kwargs.get('artifacts'))
+                      artifacts='full_payload,test_suites,autotest,stateful',
+                      async=async)
 
   @cherrypy.expose
   def stage_debug(self, **kwargs):