Site Icon: make the default value for the site_icon option 0 in schema.php.

Props swissspidy, sebastian.pisula.
Fixes #34339.


git-svn-id: https://develop.svn.wordpress.org/trunk@35312 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/schema.php

@@ -506,6 +506,7 @@ function populate_options() {
 
 	// 4.3.0
 	'finished_splitting_shared_terms' => 1,
+	'site_icon' => 0,
 	);
 
 	// 3.3