Bump src/cloud_controller_ng

Bump deadcats/cloud_controller_ng:
  Max Brunsfeld:
     Merge pull request #294 from deadcats/docker-execution-metadata-75217010
  Peter Parente:
     Fix indentation
     Handle execution metdata when docker staging succeeds
  Julian Friedman:
     Pre-warm buildpacks
  Simon Leung:
     Allow separate configuration of diego staging and running

Signed-off-by: Max Brunsfeld <mbrunsfeld@pivotallabs.com>