Btrfs: selinux support

Add call to LSM security initialization and save
resulting security xattr for new inodes.

Add xattr support to symlink inode ops.

Set inode->i_op for existing special files.

Signed-off-by: jim owens <jowens@hp.com>

diff --cc fs/btrfs/inode.c
Simple merge

diff --cc fs/btrfs/xattr.c
Simple merge

diff --cc fs/btrfs/xattr.h
Simple merge