Fix WebConsoleFormat not using names

The logging format provides both the name and id of slaves and
instances.  Use the name when formatting for the web console just like
the TerminalFormat does.

packages/lib/logging.js

@@ -59,12 +59,10 @@ class WebConsoleFormat {
 	transform(info, options) {
 		let src = " ";
 		if (info.slave_id !== undefined) {
-			let slaveName = info.slave_id;
-			src += `s:${slaveName} - `;
+			src += `s:${info.slave_name} - `;
 		}
 		if (info.instance_id !== undefined) {
-			let instanceName = info.instance_id;
-			src += `i:${instanceName}`;
+			src += `i:${info.instance_name}`;
 		}
 		if (info.plugin) {
 			src += `${info.plugin}: `;