mon: Monitor: Forward connection features

We are relying on connection features to track OSD supported
features.  However, we were not forwarding connection features
when we forwarded a message from a peon to the leader.  That
was breaking the OSD feature tracking.

Fixes: 7051

Signed-off-by: Joao Eduardo Luis <joao.luis@inktank.com>
osd: OSDMap: dump osd_xinfo_t::features as an int

Instead of dumping the list in a string-list format, which in
retrospect wasn't very useful.

Signed-off-by: Joao Eduardo Luis <joao.luis@inktank.com>
Merge pull request #984 from ceph/wip-7051

#7051: forward connection features alongside with message

Reviewed-by: Loic Dachary <loic@dachary.org>
Reviewed-by: Sage Weil <sage@inktank.com>