rpcrt4: Add a stub for I_RpcGetCurrentCallHandle.

dlls/rpcrt4/rpc_server.c

@@ -1121,3 +1121,12 @@ RPC_STATUS WINAPI RpcMgmtSetServerStackSize(ULONG ThreadStackSize)
   FIXME("(0x%x): stub\n", ThreadStackSize);
   return RPC_S_OK;
 }
+
+/***********************************************************************
+ *             I_RpcGetCurrentCallHandle (RPCRT4.@)
+ */
+RPC_BINDING_HANDLE WINAPI I_RpcGetCurrentCallHandle(void)
+{
+    FIXME("\n");
+    return NULL;
+}

dlls/rpcrt4/rpcrt4.spec

@@ -51,7 +51,7 @@
 @ stub I_RpcGetAssociationContext
 @ stdcall I_RpcGetBuffer(ptr)
 @ stub I_RpcGetBufferWithObject
-@ stub I_RpcGetCurrentCallHandle
+@ stdcall I_RpcGetCurrentCallHandle()
 @ stub I_RpcGetExtendedError
 @ stub I_RpcGetServerContextList
 @ stub I_RpcGetThreadEvent # win9x