Drop close-without-saving confirmation dialog

Anecdotally, most users (including me) rarely want to save their logs,
they just want to record them and read them. In any case, all the
temporary logs are actually kept (forever) in $XDG_CACHE_DIR.

Fixes #15.
2 jobs for 15-no-close-confirmation in 17 minutes and 27 seconds (queued for 1 second)
Status Job ID Name Coverage
  Lint
passed #1538089
lint

00:02:52

 
  Build
passed #1538090
stack-build-test

00:14:34