btrfs: return nil on success
btrfs: return nil on success

In other words:

be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid
be less stupid

Signed-off-by: Christian Brauner <48455ab3070520a2d174545c7239d6d0fabd9a83@ubuntu.com>

jsavikko/lxd,hallyn/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,mjeanson/lxd,stgraber/lxd,erikmack/lxd,pcdummy/lxd,pcdummy/lxd,stgraber/lxd,atxwebs/lxd,hallyn/lxd,atxwebs/lxd,stgraber/lxd,pcdummy/lxd,Skarlso/lxd,stgraber/lxd,Skarlso/lxd,erikmack/lxd,stgraber/lxd,Skarlso/lxd,lxc/lxd,jsavikko/lxd,hallyn/lxd,hallyn/lxd,hallyn/lxd,jsavikko/lxd,Skarlso/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,atxwebs/lxd,lxc/lxd,erikmack/lxd,mjeanson/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,mjeanson/lxd