[PATCH] scsi_scan: check return code from scsi_sysfs_add_sdev

Adds a missing check for an error return code from scsi_sysfs_add_sdev.
This resolves entry #4863 in the OSDL bugzilla.  Although in that bug
report the failure occurred because of a confusion over scanning vs.
rescanning, in general add_sdev can fail for a number of reasons (the
simplest being insufficient memory) and the caller should cope properly.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>