cryptonote_protocol: fix missing space in version mismatch message

src/cryptonote_protocol/cryptonote_protocol_handler.inl

@@ -273,7 +273,7 @@ namespace cryptonote
       {
         if (version < hshd.top_version)
           MCLOG_RED(el::Level::Warning, "global", context << " peer claims higher version that we think (" <<
-              (unsigned)hshd.top_version << " for " << (hshd.current_height - 1) << "instead of " << (unsigned)version <<
+              (unsigned)hshd.top_version << " for " << (hshd.current_height - 1) << " instead of " << (unsigned)version <<
               ") - we may be forked from the network and a software upgrade may be needed");
         return false;
       }