- add several tools to mkinitrd if root fs is btrfs
- pull upstream branch and delete local patches

- btrfsck: ignore -a (bnc#655906)
- btrfsck: fix strerror value

- Remove redundant tags/sections from specfile
- Use %_smp_mflags for parallel build

- add patch for local version override as we do not build from
git, and avoid doubled "Btrfs" in output of 'btrfs'

- reorder help for 'get-default' right after 'set-default'

- add option -p to print parent subvolume
- add subvolume 'get-default' subsubcommand