This adds daemon/graphdriver/graphtest/graphtest which has a few
generic tests for all graph drivers, and then uses these
from the btrs, devicemapper and vfs backends.
I've not yet added the aufs backend, because i can't test that here
atm. It should work though.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: 27744062aa96f5f16d615ed829bc0d06b7df381d
Component: engine
b543168adc