dirs: convert PyString to PyBytes
PyStringObject was renamed to PyBytes in Python 3 along with the
corresponding PyString* functions and macros. PyString* doesn't
exist in Python 3. But PyBytes* is an alias to PyString in Python 2.
So rewrite PyString* to PyBytes* for Python 2/3 dual compatibility.
Issue351: mq: qrefresh can create extra revlog entry
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ hg qinit
$ echo b > b
$ hg ci -A -m foo
adding b
$ echo cc > b
$ hg qnew -f foo.diff
$ echo b > b
$ hg qrefresh
$ hg debugindex b
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 ..... 0 1e88685f5dde 000000000000 000000000000 (re)