Two notices in post_custom()

[sirzooro]

When someone will use non-existing index, PHP will display following notices:
Notice: Undefined index: views in C:\wordpress.local\wp-includes\post-template.php on line 649
Notice: Undefined index: views in C:\wordpress.local\wp-includes\post-template.php on line 652

Attached patch fixes this - when someone will use non-exiting index, post_custom() will return empty string.

[sirzooro]

Hmm, I wonder if it would be better to return null instead.

[dd32]

I've gone with returning (bool)false.

'' == false == null for displaying in a string, they'd all display as nothing, but given that bools cant be returned from the post_meta i do not believe, it seems to be the best choice in this case.

[dd32]

[13861] /trunk/wp-includes/post-template.php: Fix notices in post_custom(). Props sirzooro. Fixes #11839