wpdb::query() does not detect LOAD DATA as an insert statement type

[lev0]

The regular expression used to choose what return type a query should have does not include LOAD DATA. A query beginning with these tokens thus incorrectly returns 0 for the number of affected rows. The following patch would correct the issue:

wp-includes/wp-db.php

@@ -1973 +1973 @@
 
                if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
                        $return_val = $this->result;
-               } elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
+               } elseif ( preg_match( '/^\s*(insert|delete|update|replace|load\s+data)\s/i', $query ) ) {
                        if ( $this->use_mysqli ) {
                                $this->rows_affected = mysqli_affected_rows( $this->dbh );
                        } else {