LU-8403 obd: remove OBD_NOTIFY_SYNC{,_NONBLOCK}

LU-8403 obd: remove OBD_NOTIFY_SYNC{,_NONBLOCK}

None of the OBD notify handlers listen for OBD_NOTIFY_SYNC{,_NONBLOCK}
events so remove them and related code in lov_notify().

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I3bc2bd34b268b28777241555dae8896577150c91
Reviewed-on: https://review.whamcloud.com/21421
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>