scd,w32: Fix posssible lockup due to lost select results.

* scd/scdaemon.c (handle_connections) [W32]: Do not continue the loop
when an event was encountered.

Here the event handle is passed to npth_eselect so that this function
can detect the event and reset the event. There is no need to consume
this information here. However, npth_select might also got a ready
file descriptor along with the event and by doing a "continue" we
would miss the ready state of the file descriptor. The fix is to do
nothing here, similar to what we do in gpg-agent.

• Fixes-commit: f9acc7d18bb90f47dafe7e32ae92f567756d6b12
• GnuPG-bug-id: T2982