Require libosinfo >= 0.2.9

https://bugzilla.gnome.org/show_bug.cgi?id=719512
extract-iso: Use osinfo_db_identify_media

osinfo_db_guess_os_from_media is deprecated in newer libosinfo and
is replaced by osinfo_db_identify_media.

https://bugzilla.gnome.org/show_bug.cgi?id=719512
extract-iso: Make use of OS variants

Take the name of first variant as 'nie:title', if any.

https://bugzilla.gnome.org/show_bug.cgi?id=719512