Exclude specs from CodeClimate ratings

CodeClimate makes recommendations that, while helpful for production
code, can be harmful for test code. In particular, following its
recommendations would lead us to aggressively de-duplicate even small
amounts of test setup code. That can create unwanted coupling, obscure
the intent of the tests, and make it harder to maintain tests as their
setup needs diverge.

.codeclimate.yml

@@ -4,6 +4,7 @@ ratings:
   paths:
   - "src/**/*.js"
 exclude_paths:
+- "spec/**/*.js"
 - "lib/**"
 - "dist/*"
 - "grunt/**"