optionally run "btrfs device scan" during mountall.
optionally run "btrfs device scan" during mountall.

As reported by Bryce L Nordgren.

Multi-disk btrfs filesystems need to get assembled first before they become mountable.
Enable this by explicitly assigning fsType = "btrfs" in the filesystems list in configuration.nix

git-svn-id: 71c8032c709790ec749031c4215f8515ac00dc5a@32682 70bd8c7a-acb8-0310-9f0d-9cc1c95dcdbb

bnordgren/nixos,bnordgren/nixos,bnordgren/nixos,bnordgren/nixos,bnordgren/nixos