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/autofs4/inode.c

@@ -455,11 +455,7 @@ struct inode *autofs4_get_inode(struct super_block *sb,
 	if (sb->s_root) {
 		inode->i_uid = sb->s_root->d_inode->i_uid;
 		inode->i_gid = sb->s_root->d_inode->i_gid;
-	} else {
-		inode->i_uid = 0;
-		inode->i_gid = 0;
 	}
-	inode->i_blocks = 0;
 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 
 	if (S_ISDIR(inf->mode)) {