fix signed/unsigned in strprintf and CNetAddr::GetByte()

- I checked every occurance of strprintf() in the code and used %u, where
  unsigned vars are used
- the change to GetByte() was made, as ip is an unsigned char

src/bitcoinrpc.cpp

@@ -816,7 +816,7 @@ void ThreadRPCServer2(void* parg)
     }
     catch(boost::system::system_error &e)
     {
-        strerr = strprintf(_("An error occurred while setting up the RPC port %i for listening on IPv4: %s"), endpoint.port(), e.what());
+        strerr = strprintf(_("An error occurred while setting up the RPC port %u for listening on IPv4: %s"), endpoint.port(), e.what());
     }
 
     if (!fListening) {