overlay: Remove unused method param
overlay: Remove unused method param

`getCleanupDirectories` didn't use the storage transactor.

Signed-off-by: Danny Canter <df4bf92e16bbb7396c50d637f6b7ad9a4c8c274c@dcantah.dev>

thaJeztah/containerd,containerd/containerd,thaJeztah/containerd,mikebrow/containerd,mikebrow/containerd,containerd/containerd