ODF import: detect "LibreOfficeDev" in meta:generator too

(cherry picked from commit 74d7911abf77643544c58a0d3e5fb956add76c44)

xmloff: we used to call it LOdev back in 4.0 so check that too
(cherry picked from commit 5d53cabb52648507086a39e06803624949e4a301)

Change-Id: Icea3086975dab1afedf111364683e6a7de50ce41
Reviewed-on: https://gerrit.libreoffice.org/9063
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>