use lsr-gh-action-py26 for python 2.6 unit tests
use lsr-gh-action-py26 for python 2.6 unit tests

Use the new https://github.com/linux-system-roles/lsr-gh-action-py26
for running unit tests on python 2.6.  This uses an EL6 VM so more
closely corresponds to the managed hosts that still use python 2.6.

Signed-off-by: Rich Megginson <eddfb389174a82ceee7387bfddd9793f5b4725f4@redhat.com>

linux-system-roles/network,linux-system-roles/network,linux-system-roles/network