LibVNCClient: don't leak uninitialised memory to remote

The pad fields of the rfbClientCutTextMsg and rfbKeyEventMsg could contain arbitray memory belonging to the process,
don't leak this to the remote.

Closes #252

libvncclient/rfbproto.c

@@ -1643,6 +1643,7 @@ SendKeyEvent(rfbClient* client, uint32_t key, rfbBool down)
 
   if (!SupportsClient2Server(client, rfbKeyEvent)) return TRUE;
 
+  memset(&ke, 0, sizeof(ke));
   ke.type = rfbKeyEvent;
   ke.down = down ? 1 : 0;
   ke.key = rfbClientSwap32IfLE(key);
@@ -1661,6 +1662,7 @@ SendClientCutText(rfbClient* client, char *str, int len)
 
   if (!SupportsClient2Server(client, rfbClientCutText)) return TRUE;
 
+  memset(&cct, 0, sizeof(cct));
   cct.type = rfbClientCutText;
   cct.length = rfbClientSwap32IfLE(len);
   return  (WriteToRFBServer(client, (char *)&cct, sz_rfbClientCutTextMsg) &&