[cobaltb.py] Don't print backtrace in check_config

This should make registry  errors easier to read

Change-Id: Iebb67f6dc9b69ee7d8537115605f29bda48e0a28
Reviewed-on: https://fuchsia-review.googlesource.com/c/cobalt/+/490903
Fuchsia-Auto-Submit: Zach Bush <zmbush@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Reviewed-by: Jared Weinstein <jaredweinstein@google.com>
diff --git a/cobaltb.py b/cobaltb.py
index accfce7..97d30e7 100755
--- a/cobaltb.py
+++ b/cobaltb.py
@@ -217,10 +217,13 @@
     return
   if not args.skip_check_test_configs and not _check_test_configs(args):
     return
-  subprocess.check_call([
-      config_parser_bin, '-config_dir', args.config_dir, '-check_only',
-      '-privacy_encoding_params_file', args.privacy_encoding_params_file
-  ])
+  try:
+    subprocess.check_call([
+        config_parser_bin, '-config_dir', args.config_dir, '-check_only',
+        '-privacy_encoding_params_file', args.privacy_encoding_params_file
+    ])
+  except subprocess.CalledProcessError:
+    sys.exit(1)
 
 
 def _check_test_configs(args):