Removed some dead code in the master.
Removed some dead code in the master.

Master generated status update will go through the `forward` interface
now. This code path is no longer used.

Review: https://reviews.apache.org/r/64233

asamerh4/mesos,andschwa/mesos,gsantovena/mesos,jpeach/mesos,jpeach/mesos,asamerh4/mesos,gsantovena/mesos,dforsyth/mesos,jpeach/mesos,abudnik/mesos,gsantovena/mesos,chhsia0/mesos,reneploetz/mesos,dforsyth/mesos,gsantovena/mesos,kaysoky/mesos,reneploetz/mesos,Gilbert88/mesos,chhsia0/mesos,Gilbert88/mesos,andschwa/mesos,kaysoky/mesos,dforsyth/mesos,Gilbert88/mesos,jpeach/mesos,gsantovena/mesos,chhsia0/mesos,asamerh4/mesos,chhsia0/mesos,asamerh4/mesos,gsantovena/mesos,Gilbert88/mesos,kaysoky/mesos,gsantovena/mesos,Gilbert88/mesos,dforsyth/mesos,reneploetz/mesos,abudnik/mesos,andschwa/mesos,reneploetz/mesos,jpeach/mesos,abudnik/mesos,Gilbert88/mesos,jpeach/mesos,jpeach/mesos,kaysoky/mesos,andschwa/mesos,dforsyth/mesos,dforsyth/mesos,andschwa/mesos,andschwa/mesos,abudnik/mesos,reneploetz/mesos,abudnik/mesos,reneploetz/mesos,Gilbert88/mesos,dforsyth/mesos,reneploetz/mesos,asamerh4/mesos,chhsia0/mesos,kaysoky/mesos,chhsia0/mesos,asamerh4/mesos,abudnik/mesos,kaysoky/mesos,abudnik/mesos,chhsia0/mesos,kaysoky/mesos,andschwa/mesos,asamerh4/mesos