From Michael Osias (IBM)

This patch implements the llHttpRequest function via a region module,
HttpScriptsRequest.  There were bits and peices in LSLLong_cmd_handler,
which I moved into the region module, and just check for completed
requests and dispatch the http_response callback event instead.

works for me as of r2674

OpenSim/Region/Environment/Modules/XMLRPCModule.cs

@@ -121,7 +121,7 @@ namespace OpenSim.Region.Environment.Modules
 
         public bool IsSharedModule
         {
-            get { return false; }
+            get { return true; }
         }
 
         /**********************************************