xbuddy: remove DEV from GS_ALIAS

This would fix the alias-to-filename mapping because there are no
correspoinding entries in GS_FILE_NAMES and ARTIFACTS for the dev
image. The alternative is to add the missing entries, but we cannot
produce dev image anyway because it is not included in image.zip.

BUG=chromium:342196
TEST=None

Change-Id: Ic53484f291f141f224997f4cd88275ff66900321
Reviewed-on: https://chromium-review.googlesource.com/185668
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Yu-Ju Hong <yjhong@chromium.org>
Tested-by: Yu-Ju Hong <yjhong@chromium.org>
diff --git a/xbuddy.py b/xbuddy.py
index ff480aa..cb8fdbc 100644
--- a/xbuddy.py
+++ b/xbuddy.py
@@ -79,7 +79,6 @@
 # Google Storage constants
 GS_ALIASES = [
   TEST,
-  DEV,
   BASE,
   RECOVERY,
   FULL,