Add the methods to the Driver interface
to force the drivers to implement the methods
Upstream-commit: 4d1a537433ede2bbc75b0a4817e8121f9e03fd86
Component: engine
This moves the Diff() operation to a separate Differ interface and
implements a fallback that uses the Changes() results to encode
a diff tar.
Upstream-commit: e82f8c1661f3fa18e4dc6ca3aebe4dcc46e8961b
Component: engine
We now always initialize devicemapper on startup, so
no need for the code that did lazy initialization, we
just delete it.
Upstream-commit: b5795749d1688f99df422dd7068b189e5b25e5e9
Component: engine
