Reintroduce transactionID to the parameter list for SendInstantMessage.

It is required by group IM and also for a proper implementation of item
give, group notice attachments and offline IM.

OpenSim/Framework/IClientAPI.cs

@@ -741,7 +741,7 @@ namespace OpenSim.Framework
                                 uint timeStamp);
 
         void SendInstantMessage(UUID fromAgent, string message, UUID toAgent, string fromName, byte dialog,
-                                uint timeStamp, bool fromGroup, byte[] binaryBucket);
+                                uint timeStamp, UUID transactionID, bool fromGroup, byte[] binaryBucket);
 
         void SendGenericMessage(string method, List<string> message);
 
@@ -1027,4 +1027,4 @@ namespace OpenSim.Framework
 
         void KillEndDone();
     }
-}
+}