moblab: Ensure no upload to apfe from moblab

The default config sets a bucket for the cts files to be uploaded
to apfe, this is an error in moblab since there are no permissions
to access that bucket.  Clear out the setting using the shadow config.

TEST=local testing
BUG=chromium:665546

Change-Id: I574bc76ea39979efacca8f2b488bcd9f7132ac30
Reviewed-on: https://chromium-review.googlesource.com/411378
Commit-Ready: Keith Haddow <haddowk@chromium.org>
Tested-by: Keith Haddow <haddowk@chromium.org>
Reviewed-by: Keith Haddow <haddowk@chromium.org>
Reviewed-by: Michael Tang <ntang@chromium.org>
diff --git a/moblab_config.ini b/moblab_config.ini
index 4878587..815bbf8 100644
--- a/moblab_config.ini
+++ b/moblab_config.ini
@@ -23,4 +23,5 @@
 [CROS]
 # In moblab, this paramater is empty and uses the image bucket by default.
 results_storage_server:
+cts_results_server:
 stable_cros_version: R53-8480.0.0