Reduce log spam on connection error

Print only the error message in the console when a connection error is
encountered on the link connector.  This reduces log spam on reconnect
for slaves.

packages/lib/link/connectors.js

@@ -315,7 +315,7 @@ class WebSocketClientConnector extends WebSocketBaseConnector {
 
 		this._socket.onerror = event => {
 			// It's assumed that close is always called by ws
-			console.error("SOCKET | Error:", event);
+			console.error("SOCKET | Error:", event.message || "unknown error");
 		};
 
 		this._socket.onopen = () => {