Snapshot: Check that / is a btrfs subvolume before setup
Skip setup the snapshots app if the filesystem type is btrfs but / is not a btrfs subvolume. For example, this may happen in a containers where / is a bind mounted btrfs filesystem.
Closes #1994 (closed)
Tests performed:
- Install freedombox on a lxc container inside Pioneer-FreedomBox. (In a container, / is a bind mounted btrfs filesystem). The snapshot app setup is skipped.
- Install freedombox inside dev container (which uses btrfs filesystem image). The snapshot app setup succeeds.
- Install freedombox inside container that uses a host directory as a base and the filesystem is ext4. The snapshot app setup is skipped.
Signed-off-by: Veiko Aasa veiko17@disroot.org