Patch up the CRUSH map compatibility guards

The "ceph osd crush tunables optimal" and "ceph osd setcrushmap" commands left an incompatibility window. Close it by testing the proposed CRUSH change feature requirements against the existing cluster's feature bits.
the message below (i.e. if unsupported_count > 0) won't show which feature are mismatched in which daemon, just that some of them. What about including the diff in the message ?