Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Max Brunsfeld:
     Mark app as staged after receiving staging completion message ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/30115498 )
  Abhijit Hiremagalur:
     Simplify AppFactory ( Travis Unknown )
     Avoid overloading app.droplet_hash= ( Travis Unknown )
  Graeme Davison and James Myers:
     Update Readme to mention cc_test database before running specs ( Travis finished: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/30031345 )

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>