Multi-site support: When one site is down channel manager is sometimes unavailable

Steps to reproduce:
1) Start testsuite and open the CMS
2) Stop the intranet webapp [1]
3) Logout and login the CMS
Expected: Channel Manager is available
Actual: Channel Manager icon is missing
When clicking on the void, an error is displayed:

An error has occurred, sorry for that.

org.apache.cxf.jaxrs.client.ServerWebApplicationException:
Failed to instantiate plugin class 'org.onehippo.cms7.channelmanager.ChannelManagerPerspective' for wicket id 'service.tab' in plugin 'home.cluster.cms-static.plugin.channelManagerLoader.cluster.hippo-channel-manager.plugin.channel-manager-perspective' (JcrPluginConfig:/hippo:configuration/hippo:frontend/cms/hippo-channel-manager/channel-manager-perspective)
Hippo CMS 7

On the console:
[INFO] [talledLocalContainer] 2014-06-25 12:17:25,597 WARN [http-bio-8080-exec-19] [org.onehippo.cms7.channelmanager.channels.ChannelStore.loadChannels():541] Failed to load the channels for one or more rest proxies: java.util.concurrent.ExecutionException: Status : 404
[INFO] [talledLocalContainer] Headers :
[INFO] [talledLocalContainer] Content-Length : 0
[INFO] [talledLocalContainer] Date : Wed, 25 Jun 2014 10:17:25 GMT
[INFO] [talledLocalContainer] Server : Apache-Coyote/1.1
[INFO] [talledLocalContainer]
[INFO] [talledLocalContainer] 2014-06-25 12:17:33,293 ERROR [http-bio-8080-exec-21] [org.onehippo.cms7.channelmanager.channels.BlueprintStore.getBlueprints():135] Failed to load blueprint for one or more rest proxies.
[INFO] [talledLocalContainer] java.util.concurrent.ExecutionException: Status : 404
[INFO] [talledLocalContainer] Headers :
[INFO] [talledLocalContainer] Content-Length : 0
[INFO] [talledLocalContainer] Date : Wed, 25 Jun 2014 10:17:33 GMT
[INFO] [talledLocalContainer] Server : Apache-Coyote/1.1
[INFO] [talledLocalContainer]
[INFO] [talledLocalContainer] at java.util.concurrent.FutureTask.report(FutureTask.java:122)
[INFO] [talledLocalContainer] at java.util.concurrent.FutureTask.get(FutureTask.java:188)
[INFO] [talledLocalContainer] at org.onehippo.cms7.channelmanager.channels.BlueprintStore.getBlueprints(BlueprintStore.java:131)
[INFO] [talledLocalContainer] at org.onehippo.cms7.channelmanager.channels.BlueprintStore.getTotal(BlueprintStore.java:71)
[INFO] [talledLocalContainer] at org.onehippo.cms7.channelmanager.channels.BlueprintStore.isEmpty(BlueprintStore.java:75)
[INFO] [talledLocalContainer] at org.onehippo.cms7.channelmanager.RootPanel.<init>(RootPanel.java:132)
[INFO] [talledLocalContainer] at org.onehippo.cms7.channelmanager.ChannelManagerPerspective.<init>(ChannelManagerPerspective.java:72)

[1] Go to http://localhost:8080/manager/, login with admin/<empty> and stop the webapp