Comment 5 for bug 1722364

Ah right, the empty string check should have been added there as well (even though empty data seems to be currently discarded at https://sourceforge.net/p/dcplusplus/code/ci/f8540557bd5c28a9d0b3879b3e6b26f50ab670a6/tree/dcpp/SearchManager.cpp#l132). The old NMDC code was moved as it was as I don't even want to understand the logic in it.....