fix handling of multiple Content-type headers
This can happen if an error happens while sending
application/mercurial-0.1 content. The error page will
be sent resulting (for at least lighttpd) in the following
headers:
Content-type: application/mercurial-0.1
Content-type: text/html
which result in req.proto = 'application/mercurial-0.1, text/html'
fix issue344
port:4:export
port:4:vaportight
port:4:import/export
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import
port:4:import/export
% follow
port:0:import
port2:6:4:+:eggs:deport
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import