cbuildbot: drop CQ-DEPEND support

We haven't used CQ-DEPEND tags for a while since the new CQ doesn't
respect them, so drop the logic from chromite.

BUG=chromium:1025955
TEST=CQ passes

Change-Id: Ie353a4d781204e6fc61c10d07b466da0bd585849
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2690934
Reviewed-by: George Engelbrecht <engeg@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/gerrit.py b/scripts/gerrit.py
index d3790ad..7cf8928 100644
--- a/scripts/gerrit.py
+++ b/scripts/gerrit.py
@@ -432,10 +432,7 @@
 
   @classmethod
   def _Children(cls, opts, querier, cl):
-    """Yields the Gerrit and CQ-Depends dependencies of a patch"""
-    for change in cls._ProcessDeps(
-        opts, querier, cl, cl.PaladinDependencies(None), True):
-      yield change
+    """Yields the Gerrit dependencies of a patch"""
     for change in cls._ProcessDeps(
         opts, querier, cl, cl.GerritDependencies(), False):
       yield change