ceph_objectstore_tool: Clear ...INCOMPAT_SHARDS from feature if exporting replicated pg

Don't require importing OSD to have shards feature for replicated pg

http://tracker.ceph.com/issues/10077 Fixes: #10077

Signed-off-by: David Zafman <dzafman@redhat.com>
ceph_objectstore_tool: Add utility routine get_osdmap()

Signed-off-by: David Zafman <dzafman@redhat.com>
ceph_objectstore_tool: Add feature called set-allow-sharded-objects

Uses --op set-allow-sharded-objects option
This operation will be rejected if on the target OSD's osdmap there is
    at least one OSD which does not support ERASURE CODES.
Prompt the user that they could import if sharded state allowed
Prompt the user to use new feature if sharded state found inconsistent

Fixes: #10077

Signed-off-by: David Zafman <dzafman@redhat.com>
Merge pull request #2967 from ceph/wip-10077

ceph_objectstore_tool shard feature handling

 Reviewed-by: Loic Dachary <ldachary@redhat.com>