Add additional capabilities for computes
Add additional capabilities for computes

This allows compute hosts to advertise additional capabilities
for use by custom schedulers. This is an interim solution to
provide this functionality until it is replaced by more general
HostAggregate functionality later in Folsom.

Change-Id: Ia288146fa92aec61f50641c2e4f7a3580ab03a32

n0ano/ganttclient