add/copy checks fail if the instructions are not present in a dockerfile

[TomasTomecek]

TEST FAIL:  /usr/lib/python2.7/site-packages/moduleframework/tests/static/dockerfile_lint.py:DockerInstructionsTests.test_copy_files_exist
     reason -> Some files in the COPY or ADD instruction do not exist.
     /home/zdravomil/avocado/job-results/job-2018-03-07T05.35-34c11fb/test-results/05-_usr_lib_python2.7_site-packages_moduleframework_tests_static_dockerfile_lint.py:DockerInstructionsTests.test_copy_files_exist/debug.log

The check fails even though there are no such instructions present in the dockerfile.

(I omitted internal info)

FROM rhel7:...

LABEL description="Red Hat OpenStack Platform..."
LABEL batch="..."
LABEL version-release="..."
LABEL io.openshift.tags="rhosp osp openstack..."
LABEL summary="Red Hat OpenStack Platform..."
LABEL io.k8s.display-name="Red Hat OpenStack Platform..."
LABEL com.redhat.component="openstack-kuryr-controller-docker"
LABEL name="rhosp.../openstack-kuryr-controller"
LABEL version="..."
LABEL architecture="x86_64"

RUN yum install -y ...

USER ...
ENTRYPOINT [ "/usr/bin/..." ]