Server audit plugin not auditing when changing parameter "server_audit_events" value.

The plugin creates a log only when you change the parameter "server_audit_events" from nothing to "QUERY" but not when you change from "QUERY" to nothing.

This is problematic for security questions.

Auditing the command set global server_audit_events="..."; and the command set global server_audit_logging="..."; could improve security.