Tightened resource provider manager registrar tests.
Tightened resource provider manager registrar tests.

This patch changes tests of operations on the resource provider
manager registrar to make the operations return with a success instead
of just checking that the future results get ready.

Review: https://reviews.apache.org/r/66476/

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