fuse: reduce max out args

The third out-arg is never actually used.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

fs/fuse/fuse_i.h

@@ -213,7 +213,7 @@ struct fuse_out {
 	unsigned numargs;
 
 	/** Array of arguments */
-	struct fuse_arg args[3];
+	struct fuse_arg args[2];
 };
 
 /** FUSE page descriptor */