Combine a message as one string and give it to snet_event_log

snet_event_log gets 3 arguments. Combine a message of revoking
permission when group changed and give it to 3rd argument of
snet_event_log.

Test: Repo'd scenario and looked at log
Bug: 79443138
Change-Id: Iecf0505bb7927891aa879d0cacedcf94872b9452
1 file changed