def delete(type, hash)
      raise Dis::Errors::ReadOnlyError if readonly?
      delete!(type, hash)
    end
def delete(type, hash)
      raise Dis::Errors::ReadOnlyError if readonly?
      delete!(type, hash)
    end
Deletes a file from the store.

   layer.delete("documents", hash)

 Returns true if the file was deleted, or false if it could not be found.
 Raises an error if the layer is readonly.