LU-506 kernel: some other minor cleanup of BKL

LU-506 kernel: some other minor cleanup of BKL

Remove lock_kernel/unlock_kernel from cfs_daemonize.
Remove HAVE_UNLOCKED_IOCTL check as it is defined after 2.6.12.

Signed-off-by: Liu Xuezhao <xuezhao.liu@emc.com>
Change-Id: I6e41c0c3fa76c33dae4f820a63bd3ba62ff704ec
Reviewed-on: http://review.whamcloud.com/2950
Tested-by: Hudson
Reviewed-by: Lai Siyao <laisiyao@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>