test: create some history in test-dirstate-backup
An empty repository, based on `null` is quite a corner cases. We create a more
"natural" setup for this tests to make sure it can keep testing what it intend
to test in the future.
$ hg init repo
$ cd repo
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls -A
.hg
a
unknown