This adds support for Novell, KDE (for KOffice/Calligra), GNOME (for
Gnumeric), AbiSource (for AbiWord) bugzillas and Launchpad to
bin/get-bugzilla-attachments-by-mimetype script as required by
easyhack#46538. However, there two glitches and workarounds:

1- As stated in the code, Novell bugzilla requires users to log in to bugzilla in
order to get full information about the bugs such as attachment bodies etc. Since
Novell bugzilla uses some proprietary login extensions it's hard to implement log in
mechanism and use it via xmlrpc API. python-bugzilla claims that it supports Novell
bugzilla login but I could not make it work. As a workaround, comments containing
"Created an attachment (id=xxxxxxx)" pattern are parsed and attachments are downloaded
using urllib. Attachments are filtered using mimetype info obtained from http headers.

2- For launchpad, launchpadlib python module is used. But currently launchpad api
does not support really advanced search like bugzilla. For example, it's not possible
to search for bugs having application/pdf attachments. So, again a workaround is used. Code
iterates over all the bugs of the *libreoffice* source package and check their attachments.