chore(travis): move checks from before_scripts to scripts

If jshint (or any other ci-check) fails, Travis marks the build as "Errored" which I don't think is desider:
https://travis-ci.org/angular/angular.js/builds/14938896

.travis.yml

@@ -18,10 +18,10 @@ before_script:
   - grunt bower
   - grunt bower
   - grunt package-without-bower
-  - grunt ci-checks
   - ./lib/sauce/sauce_connect_block.sh
 
 script:
+  - grunt ci-checks
   - ./travis_build.sh
 
 after_script: