cbuildbot: fix some old pre_cq config refs

Delete more references that unittests missed.

BUG=chromium:1025955
TEST=CQ passes

Change-Id: I70d470d0e8ff7987123de329045aa6a3fa5d396a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2121481
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cbuildbot.py b/scripts/cbuildbot.py
index e1e7b11..b5864a2 100644
--- a/scripts/cbuildbot.py
+++ b/scripts/cbuildbot.py
@@ -86,9 +86,7 @@
   Returns:
     True if the builder should be a distributed_builder
   """
-  if build_config['pre_cq']:
-    return True
-  elif not options.buildbot:
+  if not options.buildbot:
     return False
   elif chrome_rev in (constants.CHROME_REV_TOT,
                       constants.CHROME_REV_LOCAL,