Coding Standards: Always use parentheses when instantiating an object.

Note: This will be enforced by WPCS 3.0.0.

Props jrf.
See #56791.

git-svn-id: https://develop.svn.wordpress.org/trunk@54891 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-http.php

@@ -581,7 +581,7 @@ class WP_Http {
 
 		// Transport claims to support request, instantiate it and give it a whirl.
 		if ( empty( $transports[ $class ] ) ) {
-			$transports[ $class ] = new $class;
+			$transports[ $class ] = new $class();
 		}
 
 		$response = $transports[ $class ]->request( $url, $args );