engine: restore checksum check

engine/net_chan.cpp

@@ -64,15 +64,7 @@ extern int  NET_ReceiveStream( int nSock, char * buf, int len, int flags );
 // We only need to checksum packets on the PC and only when we're actually sending them over the network.
 static bool ShouldChecksumPackets()
 {
-	// nillerusr: temporary solution for testing
-	return false;
-
-#if 0
-	if ( !IsPC() )
-		return false;
-
 	return NET_IsMultiplayer();
-#endif
 }
 
 bool CNetChan::IsLoopback() const