Enhancement: btrfs support in pup_event & pmount

Added 'btrfs' to pmount and drive_all (frontend_change has it already).
Corrected error in drive_all (was 'is09660').
Alphabetically reordered.

Note: in my previous commit I added 'minix' to drive_all, but didn't notice that it was already there. Corrected.

Greetings!