Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Alex Suraci and Sarah Chandler:
     fix app package cleanup when no bits are uploaded ( Travis finished: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/12062747 )
  Phan Le and Sarah Chandler:
     Removed the file after the droplets and buildpack caches are processed ( Travis Failed: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/12059295 )
     Removed the file after the app bits are processed ( Travis Unknown )
     Removed unused code ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/12019167 )
  Phan Le and Ruth Byers:
     Removed AppPackage object as its functionality is now provided by AppBitPacker. [Finished #56898266] ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11986421 )
     Removed ActiveRecord migration support ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11984171 )
     Return only the admin buildpack provided by the application when sending a staging request. [#56898266] ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11983806 )
     Add an option to support buildpack name when pushing an app. ( Travis Unknown )
  phanle:
     Move test setup to the right place ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11894604 )
  Mark Rushakoff:
     Add test instructions to README ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11878594 )
  Julz Friedman and Sarah Chandler:
     Fix tests ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11875878 )
  Julz Friedman and Ruth Byers:
     Add initial Rspec Api Documentation generation ( Travis finished: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/11875314 )