[Libreoffice] get-bugzilla-attachments-by-mimetype: slurp down bugzilla docs for regression testing

[Caolán McNamara]

bin/get-bugzilla-attachments-by-mimetype downloads public attachments of
various mimetypes from various bugzillas which can then be copied into
the appropiate "indeterminate" dirs of the various filter tests to do
some heavy duty crash/valgrind-warnings searching, e.g.

cd /my/document/horde
/path/to/bin/get-bugzilla-attachments-by-mimetype
cp ppt/* /path/to/sd/qa/unit/data/ppt/indeterminate/
cd /path/to/sd/
export VALGRIND=memcheck
make -sr

C.