tests/test-revlog-group-emptyiter.t

largefiles: remove unnecessary clearing of status fields

At the end of lfilesrepo.status(), we clear the lists of unknown,
ignored and clean files, depending on the values of 'listunknown'
etc. The lists originate from other calls to status(), and it is only
'clean' that may get updated after the calls. Let's remove the need to
clear any of the lists by explicitly only adding to 'clean' when
'listclean' is true.

Issue1678: IndexError when pushing

setting up base repo
  $ hg init a
  $ cd a
  $ touch a
  $ hg ci -Am a
  adding a
  $ cd ..

cloning base repo
  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd b

setting up cset to push
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ touch a
different msg so we get a clog new entry
  $ hg ci -Am b
  adding a
  created new head

pushing
  $ hg push -f ../a
  pushing to ../a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (+1 heads)

  $ cd ..