Fix codeclimate

We have no desire to evaluate code that's simply copied from prometheus
and test code can violate good style for legitimate reasons.

.codeclimate.yml

@@ -1,2 +1,8 @@
 exclude_patterns:
-  - "pkg/prompb/"
+  - "**/*_test.go"
+  - "pkg/prompb/" # autogenerated
+  - "pkg/promql"  # from prometheus upstream
+checks:
+  file-lines:
+    config:
+      threshold: 350 # ideal number is 300 plus a little leeway