[style] bail out early to avoid nesting

lib/hk-util.js

@@ -1030,16 +1030,15 @@ 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) {
-                // validation can fail in multiple ways
-                if (err === 'FAILED') {
-                    // we log this case, but not others for some reason
-                    Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
-                }
-                // always abort if there was an error...
-                return void w.abort();
+            // 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
+                Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
             }
-            // otherwise it was successful!
+            // always abort if there was an error...
+            return void w.abort();
         }));
     }).nThen(function () {
         // do checkpoint stuff...