Package coverage when running integration tests

If coverpkg is missing on `go test` command, only the current package
will be covered. That's the case of unit tests. For integration tests
we need to explicitly declare each package.

Docker-DCO-1.1-Signed-off-by: Fabio Falci <fabiofalci@gmail.com> (github: fabiofalci)
Merge pull request #4048 from fabiofalci/test_integration_coverage

Collect package coverage information when running integration tests