Build: Replace ensure-wordpress-config with more direct assignment

This is the same, simpler, approach as utilised at
<https://github.com/jquery/api.jquery.com/blob/v3.1.0/Gruntfile.js>.

Author: Krinkle

Gruntfile.js

@@ -20,7 +20,15 @@ grunt.initConfig( {
 				dest: "dist/resources/sri-directives.json"
 			}
 		}
-	}
+	},
+
+	wordpress: (function() {
+
+		// This fails with "Cannot find module" if the file does not exist
+		var config = require( "./config" );
+		config.dir = "dist/wordpress";
+		return config;
+	})()
 } );
 
 grunt.registerTask( "build-index", function() {
@@ -451,22 +459,12 @@ grunt.registerTask( "ensure-dist-resources", function() {
 	grunt.file.mkdir( "dist/resources" );
 } );
 
-grunt.registerTask( "ensure-wordpress-config", function() {
-	// This will fail with "Cannot find module" if the file
-	// does not exist
-	var config = require( "./config" );
-	config.dir = "dist/wordpress";
-	grunt.config.merge( {
-		wordpress: config
-	} );
-} );
-
 grunt.registerTask( "sri-generate", ["ensure-dist-resources", "sri:generate"] );
 
 // The "grunt deploy" command is automatically invoked on git-commit by the server that
 // will deploy the WordPress site.
 // Task tree: "deploy" > "wordpress-deploy" > "build-wordpress" > "build".
 grunt.registerTask( "build", ["sri-generate", "build-index"] );
-grunt.registerTask( "deploy", ["ensure-wordpress-config", "wordpress-deploy", "reload-listings"] );
+grunt.registerTask( "deploy", ["wordpress-deploy", "reload-listings"] );
 
 };