NFSv4: Convert the open and close ops to use fmode

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
int nfs_release(struct inode *inode, struct file *filp)
{
	nfs_file_clear_open_context(filp);
	return 0;
}

int nfs_release(struct inode *inode, struct file *filp)
{
	nfs_file_clear_open_context(filp);
	return 0;
}
