A relatively common problem with awesome is with mixing sticky clients
and the focus history. Once a sticky client ever had the focus, it will
always get the focus after a tag switch. This is because the focus
history is global and the sticky client is always the most recently
focused and currently visible client in the list.
Work around this by discriminating sticky clients: First try to find a
client to focus, but ignore sticky clients. When this does not find
anything, try again, but this time also consider sticky clients.
(Basically the same issue exists with clients that are on multiple tags,
but I guess that one can be ignored.)
Fixes: https://github.com/awesomeWM/awesome/issues/733
Signed-off-by: Uli Schlachter <psychon@znc.in>