swaybar: fix logging

[crondog]

Optionally turn on debugging in swaybar. I acidentally introduced
persistent logging in a previous commit

[mikkeloscar]

You should also add info about the debug option in the man page.

[crondog]

There is no swaybar man page. There is an issue for it though #375

[mikkeloscar]

I must have been thinking about one of the other sway* binaries. But then it LGTM.

[crondog]

Ah I think I know what you mean. A swaybar.1,txt ie the binary man page. That doesn't exist either

find . -name "sway*.txt"
./swaymsg/swaymsg.1.txt
./sway/sway.5.txt
./sway/sway.1.txt
./swaygrab/swaygrab.1.txt