ipv4: split out client-id test for RHEL7
Created by: bengal
NM changed behavior upstream with respect to ascii-only client-ids. Prior to 1.11.2 NM would send the client-id as is; since 1.11.2 the client-id is prefixed with a zero byte.
On RHEL7 (NM 1.12) we reverted the change to maintain the old behavior and therefore we need to also adjust tests. We have now 3 instances of the test:
- RHEL7 (old behavior)
- NM < 1.11.2 (old behavior)
- NM >= 1.11.2 (new behavior)
(I have tried only the last two cases, not the first one).