do not udevadm trigger, ceph-disk does it

do not udevadm trigger, ceph-disk does it

There is no need for osd create to call udevadm trigger action=add. By
running all actions associated with add for all block devices, it may
also trigger some race conditions. For instance, the following happens
about 10% of the time, when using dmcrypt:

 * ceph-disk prepare --dmcrypt /dev/vdb
 * /dev/vdb1 starts activating via udev
 * ceph-deploy triggers action=add
 * /dev/vdb2 udev chown root /dev/vdb2
 * /dev/vdb1 activate fails because of permission denied on /dev/vdb2
 * /dev/vdb2 udev action chown ceph /dev/vdb2

http://tracker.ceph.com/issues/13299 Fixes: #13299

Signed-off-by: Loic Dachary <loic@dachary.org>