Make compute_capabilities_filter use information from DB not RPC

Make compute_capabilities_filter directly use the data in host_state and
not the data capabilities data that is currently broadcast from the
schedulers over RPC, as this will be removed since it doesn't scale.

The filter name, compute_capabilities_filter, is kept the same to keep
backwards compatibility.

Once all the capabilities usage in scheduler filters is removed, the
capabilities RPC broadcast can be removed.

Part of bp no-compute-fanout-to-scheduler.

Change-Id: I846259b363a794803e230eaf25c69c52970b6c4f
Merge "Make compute_capabilities_filter use information from DB not RPC"