[style] bail out early to avoid nesting

lib/hk-util.js

@@ -1030,7 +1030,8 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         // Listen for messages
         //console.log(+new Date(), "Send verification request");
         Env.validateMessage(signedMsg, metadata.validateKey, w(function (err) {
-            if (err) {
+            // no errors means success
+            if (!err) { return; }
             // validation can fail in multiple ways
             if (err === 'FAILED') {
                 // we log this case, but not others for some reason
@@ -1038,8 +1039,6 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
             }
             // always abort if there was an error...
             return void w.abort();
-            }
-            // otherwise it was successful!
         }));
     }).nThen(function () {
         // do checkpoint stuff...