Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Matthew Sykes:
     Merge branch sykesm-story71328862 ( Travis Unknown )
     Update API Docs checksum ( Travis Unknown )
     Correct api doc for positioning buidpacks ( Travis Unknown )

Signed-off-by: Joseph Palermo <jpalermo@pivotallabs.com>