Bump converger, executor, nsync, runtime-metrics-server, stager

Bump cloudfoundry-incubator/converger:
  Alex Suraci:
     metrics naming consistency ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/converger/builds/36103694 )
Bump cloudfoundry-incubator/executor:
  Alex Suraci:
     metrics naming consistency ( Travis finished: https://travis-ci.org/cloudfoundry-incubator/executor/builds/36103499 )
Bump cloudfoundry-incubator/nsync:
  Alex Suraci:
     metrics naming consistency ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/nsync/builds/36103243 )
Bump cloudfoundry-incubator/runtime-metrics-server:
  Alex Suraci:
     naming consistency ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/runtime-metrics-server/builds/36102857 )
Bump cloudfoundry-incubator/stager:
  Alex Suraci:
     fix metrics test ( Travis Success: https://travis-ci.org/cloudfoundry-incubator/stager/builds/36104039 )
     make tests match code ( Travis Failed: https://travis-ci.org/cloudfoundry-incubator/stager/builds/36102410 )
     even better metric names ( Travis Failed: https://travis-ci.org/cloudfoundry-incubator/stager/builds/36101930 )
     metrics naming consistency ( Travis Failed: https://travis-ci.org/cloudfoundry-incubator/stager/builds/36101813 )