fuse: fix mknod of regular file

The wrong lookup flag was tested in ->create() causing havoc (error or
Oops) when a regular file was created with mknod() in a fuse filesystem.

Thanks to J. Cameijo Cerdeira for the report.

Kernels 2.6.18 onward are affected.  Please apply to -stable as well.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>