fuse: reject O_DIRECT flag also in fuse_create

The comment in fuse_open about O_DIRECT:

  "VFS checks this, but only _after_ ->open()"

also holds for fuse_create, however, the same kind of check was missing there.

As an impact of this bug, open(newfile, O_RDWR|O_CREAT|O_DIRECT) fails, but a
stub newfile will remain if the fuse server handled the implied FUSE_CREATE
request appropriately.

Other impact: in the above situation ima_file_free() will complain to open/free
imbalance if CONFIG_IMA is set.

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Harshavardhana <harsha@gluster.com>
Cc: stable@kernel.org