tests/test-revert-flags.t

largefiles: fix a traceback in lfconvert if a largefile is missing (issue3519)

The largefile may be missing for various reasons, including that a remote
repository was cloned without the --all-largefiles option.  Therefore, it seems
reasonable to attempt to download the missing files and failing that, abort and
indicate the affected file and revision so the user can manually fix the
problem.

  $ "$TESTDIR/hghave" execbit || exit 80

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ chmod 644 foo
  $ hg ci -qAm '644'

  $ chmod 755 foo
  $ hg ci -qAm '755'

reverting to rev 0

  $ hg revert -a -r 0
  reverting foo
  $ hg st
  M foo
  $ hg diff --git
  diff --git a/foo b/foo
  old mode 100755
  new mode 100644

  $ cd ..