Fixed: SendingAction now sets UnsupportedDataException properly as a …

[mvysny]

…cause to the ActionException.

I have a bug report saying that

Caused by org.fourthline.cling.model.action.ActionException: Error reading SOAP response message. Can't transform null or non-string/zero-length body of: (IncomingActionResponseMessage) 200 OK
       at org.fourthline.cling.protocol.sync.SendingAction.handleResponse(SendingAction.java:145)
       at org.fourthline.cling.protocol.sync.SendingAction.invokeRemote(SendingAction.java:91)
       at org.fourthline.cling.protocol.sync.SendingAction.executeSync(SendingAction.java:63)
       at org.fourthline.cling.protocol.sync.SendingAction.executeSync(SendingAction.java:51)
       at org.fourthline.cling.protocol.SendingSync.execute(SendingSync.java:54)
       at org.fourthline.cling.protocol.SendingAsync.run(SendingAsync.java:54)
       at org.fourthline.cling.controlpoint.ActionCallback.run(ActionCallback.java:151)
       at org.fourthline.cling.support.contentdirectory.callback.Browse.run(Browse.java:89)

But it's impossible to see the actual cause.

[mvysny]

Relates to #210