logd: liblog: whitelist "snet_event_log"

Dangerous bridge to cross to whitelist, who is special, who is not?
Rationalized as these events are used to catch exploits on platform.
As it stands no one should be allowed to block any messages in the
security context, not even for development purposes.

Bug: 26178938
Change-Id: Ibdc76bc0fe29ba05be168b623af1c9f41d7edbd2