patchbomb: use procutil.shellquote() instead of shlex to escape email address
This basically backs out 2cc453284d5c, and inserts procutil.shellquote()
instead. I don't care about Windows compatibility here, but shlex.quote()
can't handle byte strings on Python 3.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}