Apply the isort modifications to the entire source tree, not just the
selected python files of test-src.
Signed-off-by: David Rheinsberg <david.rheinsberg@gmail.com>
LVM2 introduced system.devices as an alternative way to filter
devices. Since we create devices in a stage the devices won't be
added to the /etc/lvm/devices/system.devices file since /etc/ is
inside the container. As a result the we can't see these devices
and will fail with "Could not find parent device".
Therefore we add support for managing our own per-service devices
file, iff a `system.devices` is present.
In all invocations of `subprocess.run` stderr and stdout were both
combined in a shared pipe, but lvm sometimes spits out notices and
informational messages on stderr and thus potentially interfering
with the data we are interested in on stdout. Separate the two.
This gets set in `open` and used in `close` but if the former
fails the latter will explode if we do not properly initialize
it. Also, we should always properly initialize things.
