url: fix parsing of ssh urls

Fix regression introduced in 61204720


that broke parsing of some ssh: urls.

An example url is ssh://git@github.com:npm/npm.git

Fixes #9072.

Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>