tests/test-gendoc-ja.t

convert: don't drop commits that are empty in the source when using --filemap

I ran into this when using `hg lfconvert --to-normal` (which uses the filemap
class internally), and saw that commits with nothing but a branch change were
dropped.  We could put in an option that only lfconvert uses internally.  But
silently dropping anything other than a commit where all changes were excluded
seems unintended.  For example, there's a message in mercurial_sink.putcommit()
if it drops an empty commit.  (And the reason that isn't kicking in here is
because lfconvert isn't passing --filemap, so the self.filemapmode conditional
there is always False.)

The naive change of `return not files` broke test-convert-filemap.t, so this is
a little more elaborate than needed for converting from largefiles.

#require docutils gettext

  $ $TESTDIR/check-gendoc ja
  checking for parse errors
  \xe8\xa4\x87\xe8\xa3\xbd\xef\xbc\x8f\xe6\x94\xb9\xe5\x90\x8d\xe3\x81\xab\xe9\x96\xa2\xe3\x81\x99\xe3\x82\x8b\xe5\xb1\xa5\xe6\xad\xb4\xe4\xbf\x9d\xe5\xad\x98\xe3\x81\xae\xe3\x81\x9f\xe3\x82\x81\xe3\x81\xab git \xe5\xb7\xae\xe5\x88\x86\xe5\xbd\xa2\xe5\xbc\x8f\xe3\x82\x92\xe4\xbd\xbf\xe7\x94\xa8(-g/--git \xe6\x8c\x87\xe5\xae\x9a\xe3\x82\x84 \xe8\xa8\xad\xe5\xae\x9a\xe3\x83\x95\xe3\x82\xa1\xe3\x82\xa4\xe3\x83\xab\xe3\x81\xa7\xe3\x81\xae [diff] git=1 \xe8\xa8\x98\xe8\xbf\xb0)\xe3\x81\x99\xe3\x82\x8b\xe3\x81\xae\xe3\x81\xa7\xe3\x81\x82\xe3\x82\x8c\xe3\x81\xb0\xe3\x80\x81 add/remove/copy/rename \xe3\x81\xa8\xe3\x81\x84\xe3\x81\xa3\xe3\x81\x9f hg \xe3\x81\xae\xe3\x82\xb3\xe3\x83\x9e\xe3\x83\xb3\xe3\x83\x89\xe3\x81\xab\xe3\x82\x88\xe3\x82\x8b\xe5\xb1\xa5\xe6\xad\xb4\xe8\xa8\x98\xe9\x8c\xb2\xe3\x82\x82\xe3\x80\x81 \xe9\x80\x9a\xe5\xb8\xb8\xe3\x81\xa8\xe5\xa4\x89\xe3\x82\x8f\xe3\x82\x8a\xe3\x81\xaa\xe3\x81\x8f\xe6\xa9\x9f\xe8\x83\xbd\xe3\x81\x97\xe3\x81\xbe\xe3\x81\x99\xe3\x80\x82 git \xe5\xb7\xae\xe5\x88\x86\xe5\xbd\xa2\xe5\xbc\x8f\xe3\x81\xae\xe8\xa9\xb3\xe7\xb4\xb0\xe3\x81\xab\xe9\x96\xa2\xe3\x81\x97\xe3\x81\xa6\xe3\x81\xaf\xe3\x80\x81 'help diffs' \xe3\x82\x92\xe5\x8f\x82\xe7\x85\xa7\xe3\x81\x97\xe3\x81\xa6\xe3\x81\x8f\xe3\x81\xa0\xe3\x81\x95\xe3\x81\x84\xe3\x80\x82 (esc)
  warning: please use " instead of ' for hg ... "..."