Naivediff fails when layers are created directly on top of
each other. Other graphdrivers which use naivediff already
skip these tests. Until naivediff is fixed, skip with overlay2
when running tests on a kernel which causes naivediff fallback.
Fix applydiff to never use the naivediff size when not applying
changes with naivediff.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Upstream-commit: 5a1b557281204964f37e81cb0776758360029555
Component: engine
17c10a9402