Bump src/prole, src/warden-docker, src/winston

Bump winston-ci/prole:
  Alex Suraci:
     support for privileged builds ( Travis Success: https://travis-ci.org/winston-ci/prole/builds/24944208 )
Bump vito/warden-docker:
  Alex Suraci:
     always permit mknod
     retry fetching repository images 3 times
Bump winston-ci/winston:
  Alex Suraci:
     deps
     jobs can be configured to have privileged builds
     use external address for websocket uri