Improve cloud variable backoff logic

Our cloud variable server refuses connections when there are too many people in
the same room. The client does have backoff logic, however that backoff counter
is being reset when the connection is initially opened, even if the connection
is immediately closed for being over capacity.

These way these interact gives a spectacular failure case. Say that there's
2000 people playing a project with cloud variables. Let's say that about 100 of
them are let in. The other 1900 clients will be constantly opening connections,
trying to get in. Those numbers are made up but it should illustrate the
problem.

To fix this we'll wait a bit before resetting the backoff counter, to make sure
that the server didn't refuse the connection. There are cleaner ways to fix
this problem, but this solution doesn't require protocol changes.

src/lib/cloud-provider.js

@@ -26,6 +26,7 @@ class CloudProvider {
         this.cloudHost = cloudHost;
 
         this.connectionAttempts = 0;
+        this._resetConnectionAttemptsTimeout = null;
 
         // A queue of messages to send which were received before the
         // connection was ready
@@ -81,9 +82,11 @@ class CloudProvider {
     }
 
     onOpen () {
-        // Reset connection attempts to 1 to make sure any subsequent reconnects
-        // use connectionAttempts=1 to calculate timeout
-        this.connectionAttempts = 1;
+        this._resetConnectionAttemptsTimeout = setTimeout(() => {
+            this.connectionAttempts = 0;
+            this._resetConnectionAttemptsTimeout = null;    
+        }, 10 * 1000);
+
         this.writeToServer('handshake');
         log.info(`Successfully connected to clouddata server.`);
 
@@ -97,6 +100,11 @@ class CloudProvider {
     }
 
     onClose (e) {
+        if (this._resetConnectionAttemptsTimeout) {
+            clearTimeout(this._resetConnectionAttemptsTimeout);
+            this._resetConnectionAttemptsTimeout = null;
+        }
+
         // tw: code 4002 is "Username Error" -- do not try to reconnect
         if (e && e.code === 4002) {
             log.info('Cloud username is invalid. Not reconnecting.');
@@ -251,6 +259,10 @@ class CloudProvider {
             clearTimeout(this._connectionTimeout);
             this._connectionTimeout = null;
         }
+        if (this._resetConnectionAttemptsTimeout) {
+            clearTimeout(this._resetConnectionAttemptsTimeout);
+            this._resetConnectionAttemptsTimeout = null;
+        }
         this.connectionAttempts = 0;
     }