Work around what appears to be a ncurses bug. The command line at the
bottom of the screen can sometimes have stray characters left behind from
the previous command. This seems to be because ncurses is ignoreing
a ``wprintw(window, "%s", " ")'' when it's in the last column of a window.
I dont know who is right, ncurses or ncftp.

This workaround also makes the code a little cleaner as a side effect. :-)