Bump converger, runtime-schema, gosub

Bump cloudfoundry-incubator/converger:
  Alex Suraci:
     backfill unit tests for lrp watcher metrics ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/converger/builds/35998572 )
Bump cloudfoundry-incubator/runtime-schema:
  Alex Suraci:
     backfill lrp convergence tests [#76563354] ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/runtime-schema/builds/35999081 )
Bump vito/gosub:
  Alex Suraci:
     remove only submodules we know to be gone