tests: prove that `hg init` works with Python 3

The previous patch made `hg init` work!

tests/test-check-py3-commands.t

@@ -1,76 +1,80
 #require py3exe
 
 This test helps in keeping a track on which commands we can run on
 Python 3 and see what kind of errors are coming up.
 The full traceback is hidden to have a stable output.
   $ HGBIN=`which hg`
 
   $ for cmd in version debuginstall ; do
   >   echo $cmd
   >   $PYTHON3 $HGBIN $cmd 2>&1 2>&1 | tail -1
   > done
   version
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   debuginstall
   no problems detected
 
 #if test-repo
 Make a clone so that any features in the developer's .hg/hgrc that
 might confuse Python 3 don't break this test. When we can do commit in
 Python 3, we'll stop doing this. We use e76ed1e480ef for the clone
 because it has different files than 273ce12ad8f1, so we can test both
 `files` from dirstate and `files` loaded from a specific revision.
 
   $ hg clone -r e76ed1e480ef "`dirname "$TESTDIR"`" testrepo 2>&1 | tail -1
   15 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 Test using -R, which exercises some URL code:
   $ $PYTHON3 $HGBIN -R testrepo files -r 273ce12ad8f1 | tail -1
   testrepo/tkmerge
 
 Now prove `hg files` is reading the whole manifest. We have to grep
 out some potential warnings that come from hgrc as yet.
   $ cd testrepo
   $ $PYTHON3 $HGBIN files -r 273ce12ad8f1
   .hgignore
   PKG-INFO
   README
   hg
   mercurial/__init__.py
   mercurial/byterange.py
   mercurial/fancyopts.py
   mercurial/hg.py
   mercurial/mdiff.py
   mercurial/revlog.py
   mercurial/transaction.py
   notes.txt
   setup.py
   tkmerge
 
   $ $PYTHON3 $HGBIN files -r 273ce12ad8f1 | wc -l
   \s*14 (re)
   $ $PYTHON3 $HGBIN files | wc -l
   \s*15 (re)
   $ cd ..
 #endif
 
   $ cat > included-hgrc <<EOF
   > [extensions]
   > babar = imaginary_elephant
   > EOF
   $ cat >> $HGRCPATH <<EOF
   > %include $TESTTMP/included-hgrc
   > EOF
   $ $PYTHON3 $HGBIN version | tail -1
   *** failed to import extension babar from imaginary_elephant: *: 'imaginary_elephant' (glob)
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
   $ rm included-hgrc
   $ touch included-hgrc
 
 Test bytes-ness of policy.policy with HGMODULEPOLICY
 
   $ HGMODULEPOLICY=py
   $ export HGMODULEPOLICY
   $ $PYTHON3 `which hg` debuginstall 2>&1 2>&1 | tail -1
   no problems detected
+
+`hg init` can create empty repos
+
+  $ $PYTHON3 `which hg` init emptyrepo