Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Abhijit Hiremagalur:
     Get rid of DesireAppMessage ( Travis Unknown )
     Use idiomatic as_json interface for diego requests ( Travis Unknown )
     Use ? in names of predicate. Delete unused method. ( Travis Unknown )

Signed-off-by: Peter Parente <pparent@us.ibm.com>