Fix multiple popup windows

The window was not deleted if an "already in use"-key was detected,
and a new one was created as the loop was reentered.

Create/delete of the popup are moved outside the loop.
A redrawwin() call is needed to have the window displayed again.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/calcurse.h

@@ -1216,6 +1216,7 @@ void wins_calendar_cleanup(void *);
 int wins_refresh(void);
 int wins_wrefresh(WINDOW *);
 int wins_doupdate(void);
+int wins_redrawwin(WINDOW *);
 int wins_layout(void);
 void wins_set_layout(int);
 unsigned wins_sbar_width(void);