mail: pass in addr to _addressencode() in bytes
_addressencode() doesn't process a unicode addr well. For example,
acc.encode('ascii') would raise UnicodeEncodeError if acc was a unicode.
This patch temporarily restores the pre-
952bf3c948f0 _addressencode().
Several tests would be broken on Python 3.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state