Right now, there's no canonical (heh) way of handling SRC_URI for
projects that have their files at launchpad.net. We need a standard way
of handling Launchpad SRC_URIs, similar to what we do with
mirror://sourceforge/ SRC_URIs.

1. Some packages use the launchpadlibrarian.net download redirect, which
results in a non-helpful server-generated number:

(gnome-catalog)
SRC_URI="http://launchpadlibrarian.net/11326737/${PN}_${PV}.orig.tar.gz

2. Some hack up interesting MY_P stuff:

(gnome-do-plugins)
MY_PN="do-plugins"
PVC=$(get_version_component_range 1-2)
PVC2=$(get_version_component_range 1-3)
SRC_URI="https://launchpad.net/${MY_PN}/${PVC}/${PVC2}/+download/${P}.tar.gz"

(avant-window-navigator-extras)
MY_P="awn-extras-applets-${PV}"
SRC_URI="https://launchpad.net/awn-extras/${PV%.*}/${PV}/+download/${MY_P}.tar.gz"

The AWN-extras ebuild is the closest to the "right" way of doing it, I
think.

So can we agree on a standard way of treating Launchpad SRC_URIs and get
the handler support into Portage?