Not all firewall tests mock subprocess.check_call and so call out to the underlying system

[Sam Betts]

On systems without iptables or iptables hidden from the test user this results in:

FileNotFoundError: [Errno 2] No such file or directory: 'iptables'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/223503

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/223503
Committed: https://git.openstack.org/cgit/openstack/ironic-inspector/commit/?id=9d95e05ba0257139d0b979f66a317a28fb2e41bc
Submitter: Jenkins
Branch: master

commit 9d95e05ba0257139d0b979f66a317a28fb2e41bc
Author: Sam Betts <email address hidden>
Date: Tue Sep 15 11:11:58 2015 +0100

    Add mock for check_call to all firewall tests

    On systems where the iptables isn't available to test environment,
    subprocess.check_call fails with a FileNotFoundError, this patch
    ensures that all firewall tests mock check_call so its not calling
    out to the underlying test environment.

    Change-Id: Iad56638a992f922db9de00d9036b5b1ce091a411
    Closes-Bug: #1495907