Pass '--object-sync-timeout 30' to radosgw-agent

http://tracker.ceph.com/issues/7749

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Merge pull request #227 from ceph/wip-7749

Pass '--object-sync-timeout 30' to radosgw-agent

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>