zero i_uid/i_gid on inode allocation

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/inode.c

@@ -131,6 +131,8 @@ struct inode *inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_op = &empty_iops;
 	inode->i_fop = &empty_fops;
 	inode->i_nlink = 1;
+	inode->i_uid = 0;
+	inode->i_gid = 0;
 	atomic_set(&inode->i_writecount, 0);
 	inode->i_size = 0;
 	inode->i_blocks = 0;