Ever since lxc gained snap support, it assumed that if SNAP is set in
it's environment that lxc itself was running as a SNAP. This is not
necessarily the case when git-ubuntu itself is a classic snap (and thus
has SNAP set in its environment) but is calling lxc in the host. Unset
SNAP manually on lxc run() calls.
This fails hard in the dictionary comprehension over timestamps since it
expects tuples of items instead of a list of keys. Use items() to
correctly provide the former.
import_patches_applied_tree: use correct quilt env
When quilt runs, we must use GitUbuntuRepository:quilt_env in order to
make sure that QUILT_* environment variables are set correctly.
Otherwise we rely on the importer runner having the correct quilt
environment set, which may not be the case.
Also see LP 1734137: separately we need to ensure that any /etc/quiltrc
or ~/.quiltrc is ignored correctly, but I'm treating that as a separate
bug as it needs a more significant refactor to wrap all quilt calls. We
should fix that bug before declaring hash stability, but it isn't as
important as this fix as that one is less likely to be a problem in
practice on our production importer.