get-bugzilla-attachments-by-mimetype: more Python 3 in exception handler

... and also fix the print functions that shouldn't output a newline.

Change-Id: Ifd866cb33b3ef9a2e83625ed03d5cb836c1ba56b
get-bugzilla-attachments-by-mimetype: add some missing mime types

... which are officially registered on
https://www.iana.org/assignments/media-types/application

... plus some more non-standard ones for FreeHand, Keynote, ClarisWorks.

For Apple Keynote there are 2 different ones that appear to be widely
used.

Change-Id: I26d4a85733a744188cc87a78fdba0d9d3f44da96
get-bugzilla-attachments-by-mimetype: better test for existing file

Change-Id: I208a74d11945986d0712970999dbd33c03efe488
get-bugzilla-attachments-by-mimetype: more launchpad fixes

- look at more interesting packages on lanuchpad, not just libreoffice.
- the searchTasks method by default does not return closed tasks,
  and there does not appear to be a documented wild card search,
  so stupidly enumerate all possible status.

Change-Id: I51691506874722a1d8eea4755513edf50164cf9d