Integration between JIRA and HipChat Cloud fails

Summary

After installing the HipChat plugin from Marketplace and trying to configure the integration, there is an error that stops the installation of the plugin to complete.

Steps to Reproduce

1. Install JIRA
2. Install the latest HipChat plugin
3. Go to Administration > System > Hip Chat integration and hit Connect (to automatically link to your Cloud instance of HipChat)

Expected Results

1. The installation finishes successfully.

Actual Results

1. The interface of your Cloud instance appears with an option to Install the left components
2. An error pops asking you to re-install the plugin
3. The following appears on the logs:

   2015-03-31 15:04:36,389 http-bio-8080-exec-5 WARN lester.crawford 904x74444x1 i771jt 10.86.148.113,127.0.0.1 /rest/hipchat/integration/latest/installation/complete [plugins.hipchat.rest.HipChatLinkResource] Error converting response to [com.atlassian.hipchat.api.session.GenerateTokenResult] (status code 400): {
     "error": "invalid_scope",
     "error_description": "Requested scopes are not allowed for this client"
   }
   java.lang.Exception: Error converting response to [com.atlassian.hipchat.api.session.GenerateTokenResult] (status code 400): {
     "error": "invalid_scope",
     "error_description": "Requested scopes are not allowed for this client"
   }
   	at com.atlassian.hipchat.api.DefaultClientResponseMapper.makeResourceError(DefaultClientResponseMapper.java:109)
   	at com.atlassian.hipchat.api.DefaultClientResponseMapper.access$100(DefaultClientResponseMapper.java:22)
   	at com.atlassian.hipchat.api.DefaultClientResponseMapper$1.apply(DefaultClientResponseMapper.java:32)
   	at com.atlassian.hipchat.api.DefaultClientResponseMapper$1.apply(DefaultClientResponseMapper.java:28)
   	at com.google.common.base.Functions$FunctionComposition.apply(Functions.java:205)
   	at com.google.common.util.concurrent.Futures$4.apply(Futures.java:477)
   	at com.google.common.util.concurrent.Futures$4.apply(Futures.java:475)
   	at com.google.common.util.concurrent.Futures$ChainingListenableFuture.run(Futures.java:826)
   	at com.google.common.util.concurrent.MoreExecutors$SameThreadExecutorService.execute(MoreExecutors.java:253)
   	at com.google.common.util.concurrent.ExecutionList$RunnableExecutorPair.execute(ExecutionList.java:161)
   	at com.google.common.util.concurrent.ExecutionList.execute(ExecutionList.java:146)
   	at com.google.common.util.concurrent.AbstractFuture.done(AbstractFuture.java:235)
   	at com.google.common.util.concurrent.AbstractFuture.set(AbstractFuture.java:172)
   	at com.google.common.util.concurrent.SettableFuture.set(SettableFuture.java:53)
   	at com.atlassian.hipchat.api.ResourceMapper$9.onComplete(ResourceMapper.java:152)
   	at com.sun.jersey.api.client.AsyncWebResource$3.done(AsyncWebResource.java:746)
   	at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:380)
   	at java.util.concurrent.FutureTask.set(FutureTask.java:229)
   	at com.sun.jersey.client.impl.async.FutureClientResponseListener.onComplete(FutureClientResponseListener.java:107)
   	at com.sun.jersey.api.client.AsyncWebResource$6.done(AsyncWebResource.java:804)
   	at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:380)
   	at java.util.concurrent.FutureTask.set(FutureTask.java:229)
   	at java.util.concurrent.FutureTask.run(FutureTask.java:270)
   	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
   	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
   	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
   	at java.lang.Thread.run(Thread.java:745)
   

Workaround

1) go to HipChat Integration page in JIRA, and Remove the integration . Don't worry that all your mappings to projects and rooms are not deleted
2) go to https://hipchat.com/admin/addons
3) There shouldn't be any JIRA's plugin. If there is, just Uninstall it.
4) With both environments clean (with no JIRA addon installed in HC) you can do the installation again, and things should work