Support searching for `'0'` in `WP_Query`.

Props swissspidy.
See #31025.
Built from https://develop.svn.wordpress.org/trunk@36278


git-svn-id: http://core.svn.wordpress.org/trunk@36245 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/query.php

@@ -2775,7 +2775,7 @@ class WP_Query {
 		}
 
 		// If a search pattern is specified, load the posts that match.
-		if ( ! empty( $q['s'] ) ) {
+		if ( strlen( $q['s'] ) ) {
 			$search = $this->parse_search( $q );
 		}
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-alpha-36277';
+$wp_version = '4.5-alpha-36278';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.