Removed redundant 'toUnreserved()' call in the allocator.
Removed redundant 'toUnreserved()' call in the allocator.

This call is no longer necessary as the reservation metadata is now
stripped by `createStrippedScalarQuantity`.

Review: https://reviews.apache.org/r/67773/

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