Coding Standards: Use strict comparison in get_blog_id_from_url().

Follow-up to [https://mu.trac.wordpress.org/changeset/1538 mu:1538].

Props debarghyabanerjee.
See #62283.

git-svn-id: https://develop.svn.wordpress.org/trunk@59512 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/ms-functions.php

@@ -341,7 +341,7 @@ function get_blog_id_from_url( $domain, $path = '/' ) {
 	$path   = strtolower( $path );
 	$id     = wp_cache_get( md5( $domain . $path ), 'blog-id-cache' );
 
-	if ( -1 == $id ) { // Blog does not exist.
+	if ( -1 === $id ) { // Blog does not exist.
 		return 0;
 	} elseif ( $id ) {
 		return (int) $id;