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.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}