Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Joseph Palermo:
     Backfill specs for eager loaded sti association ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/28551530 )
     Disable RSpec "should" syntax. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/28546673 )
     Use transpec to remove deprecated RSpec syntax ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/28545344 )
     Update to RSpec 3 ( Travis Unknown )
     Fix RSpec deprecation warnings ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/28542628 )