cleanup temporary directory when restarting and not using XDG_RUNTIME_DIR

fixes #1253
Bugfix: prevent unneeded render on pointer enter

When `focus_follows_mouse` option is on, prevent an uneeded render on
pointer enter when the con is already focused.

This pointer enter might be caused by entering a window decoration of an
already-focused container.

This extra render can cause concurrency issues when focus is set
asynchronously with WM_TAKE_FOCUS.