test: Delete Docker image during import / export
test: Delete Docker image during import / export

This is so that we can be confident the import works and re-imports the
image into the registry (rather than the import app just using the image
which continues to exist from the export app).

Signed-off-by: Lewis Marshall <748e1641a368164906d4a0c0e3965345453dcc93@lmars.net>

lmars/flynn,lmars/flynn,lmars/flynn,philiplb/flynn,philiplb/flynn,flynn/flynn,lmars/flynn,flynn/flynn,flynn/flynn,lmars/flynn,philiplb/flynn,flynn/flynn,philiplb/flynn,philiplb/flynn,flynn/flynn