res_hep: hepv3_is_loaded() should check if we are enabled

res_hep_pjsip.so and res_hep_rtcp.so will still load and do a lot of
unnecessary work even if 'enabled' is set to 'no' in hep.conf.

Change-Id: I3eddfeea09c6b5bc7c641952ee0ae487fd09b64b

res/res_hep.c

@@ -423,7 +423,7 @@ int hepv3_is_loaded(void)
 {
 	RAII_VAR(struct module_config *, config, ao2_global_obj_ref(global_config), ao2_cleanup);
 
-	return (config != NULL) ? 1 : 0;
+	return config && config->general->enabled;
 }
 
 struct hepv3_capture_info *hepv3_create_capture_info(const void *payload, size_t len)