Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Chris Adams:
     Merge pull request #188 from fraenkel/addbuildpacks ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/22044518 )
  Ruth Byers:
     On drain, unregister from the router and wait before shutting down ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/21981348 )
  fraenkel:
     Use the new buildpack installer task ( Travis Unknown )

Signed-off-by: Kai Zhang <kaizhang@cn.ibm.com>
Move CC drain script from nginx_drain.rb to drain.rb

* It's a drain for all of CC, not just nginx.

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Abhijit Hiremagalur:
     Reduce knowledge about the db in positioner ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/22055319 )
     Encapsulate shift_to_position in update ( Travis Unknown )
     Extract BuildpackPositioner ( Travis Unknown )
     Need to call destroy to exercise after_destroy ( Travis Unknown )
     Remove dead code related to prioritized buildpacks ( Travis Unknown )
Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Abhijit Hiremagalur:
     Split responsibilities of calculating position and shifting ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/22063632 )
     Positioner no longer know about Buildpack.db ( Travis Unknown )
     Be defensive about hash key style ( Travis Unknown )