Make _create_security_group_rule non-private

_create_security_group_rule() is currently private
which is not necessarily required to be private

Implements: blueprint tempest-scenario-manager-stable
Signed-off by: Soniya Vyas<svyas@redhat.com>

Change-Id: I0e8800d20e3cbb0d8290e4a1372a2ba543288d17
3 files changed