XmlRequestHandler: name current thread
XmlRequestHandler: name current thread

The current thread that handles a XML request is named to have
a better name in logs.

Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server