Fix color updates when changing client focus from key events

This patch was originally posted on this Arch Linux forum thread:

  https://bbs.archlinux.org/viewtopic.php?id=176489

It was created against the combined wmii+ixp release found here:

  http://dl.suckless.org/wmii/wmii+ixp-3.9.2.tbz

I'm having a hard time remembering the details of the bug [this patch
fixes] now, but here is the e-mail I sent to Kris Maglione and Arch's
wmii package maintainer if you're interested:

> The problem comes down to the focusout() function in cmd/wmii/event.c.
> It tests for the condition that the event's mode is NotifyGrab and
> there is a KeyPress event later in the queue, and if both of these
> fail then it proceeds to handle the FocusOut event, eventually
> clearing disp.focus to c_magic in focusout_event()
> (cmd/wmii/client.c).  Then, when the KeyPress event finally does
> arrive, client_focus() is unable to update the previously-focused
> client's border with normcolors because disp.focus was already
> cleared.
>
> My fix simply tweaks focusout()'s logic so that the else branch never
> executes if ev->mode == NotifyGrab, regardless of whether there's a
> KeyPress event in the queue yet.  I don't know whether it should be
> considered a bug in X that we received a FocusOut-NotifyGrab event
> before the KeyPress event is available, but this change seems to work.

Corey