mta_additional: add policy module

mta_additional.te

@@ -0,0 +1,8 @@
+policy_module(mta_additional, 0.0.1)
+
+require {
+  type system_mail_t;
+}
+
+phpfpm_dontaudit_rw_stream_sockets(system_mail_t)
+phpfpm_dontaudit_rw_tcp_sockets(system_mail_t)