tests: device_messaging: add test cases
tests: device_messaging: add test cases

- test_get_session_challenge_rsp
- test_get_session_challenge_rsp_cc_not_ok

Signed-off-by: Heiko Thiery <965a85d69f7aa0aa83bbdecf1b37e17133c01ac3@gmail.com>

kontron/python-ipmi