tests/test-mq-qsave.t

sparse: move config file writing into core

The code was refactored during the move to be more procedural
instead of using string formatting. This has the benefit of not
writing empty sections, which changed tests.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init

  $ echo 'base' > base
  $ hg ci -Ambase
  adding base

  $ hg qnew -mmqbase mqbase

  $ hg qsave
  $ hg qrestore 2
  restoring status: hg patches saved state