wireshark: update to 1.12.1 (latest stable)

There are no references to g_memmove in the source anymore, so remove
the now unneeded (and failing!) sed fixup.

Sourceforge no longer has wireshark sources, the page tells users to
download from www.wireshark.org instead. So do that.
wireshark: add CLI and Qt versions

In addition to our existing GTK version.

* Only install desktop file if building a GUI version.
* The Qt build appends "-qt" to the
  wireshark binary name. Undo it so the desktop file works.
* The 'wireshark' attribute still refers to the GTK version, for
  backwards compatibility.
wireshark: fix meta.description