delete_option() does not handle blank $option values

[jsmoriss]

Both add_option() and update_option() use the following before calling wp_protect_special_option(), but delete_option() does not:

$option = trim($option);
if ( empty($option) )
    return false;

    wp_protect_special_option( $option );

I would suggest adding it delete_option() so it can handle blank $option values more elegantly.

[SergeyBiryukov]

Duplicate of #23289.