scsi: scsi_dh_alua: Ensure that alua_activate() calls the completion function

scsi: scsi_dh_alua: Ensure that alua_activate() calls the completion function

BugLink: http://bugs.launchpad.net/bugs/1681875
commit 7cb689fe42927281b8d98606ae5450173fcc66a9 upstream.

Callers of scsi_dh_activate(), e.g. dm-mpath, assume that this function
either returns an error code or calls the completion function. Make
alua_activate() call the completion function even if scsi_device_get()
fails.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Tang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>