tests/test-diff-issue2761.t

obsfate: add obsfate to default mapfile

Use the verbosity aware template keyword introduced earlier. It has the nice
property of being verbosity dependent but in order to customize the obsfate
part, users will need to replace the lobsfate definition from default mapfile
with the one using template functions (by copying the one from test-obsmarker-
template.t for example).

As it's a more advanced use-case, I'm more inclined to have the same code for
the {obsfate} keyword, in the changeset printer and in the default mapfile for
consistency.

But, the definition in default mapfile could be replaced with one based on
template filter to obsfate output customization if it is a big need for users.

Test issue2761

  $ hg init

  $ touch to-be-deleted
  $ hg add
  adding to-be-deleted
  $ hg ci -m first
  $ echo a > to-be-deleted
  $ hg ci -m second
  $ rm to-be-deleted
  $ hg diff -r 0

Same issue, different code path

  $ hg up -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ touch does-not-exist-in-1
  $ hg add
  adding does-not-exist-in-1
  $ hg ci -m third
  $ rm does-not-exist-in-1
  $ hg diff -r 1