[core, mod_cidlookup] Free memory allocated via strdup

In mod_cidlookup and several other modules, config parameters
are read from external XML files using the SWITCH_CONFIG_ITEM_STRING_STRDUP
method.  These items do not have string_options, and are not freed
with switch_xml_config_cleanup.  We therefore need to call switch_safe_free
for config without string_options.  We also add switch_xml_config_cleanup
to mod_cidlookup.  There are other modules that may be affected but this
commit makes no attempt at fixing those.

Fixes #1752

src/mod/applications/mod_cidlookup/mod_cidlookup.c

@@ -845,6 +845,7 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_cidlookup_load)
   Macro expands to: switch_status_t mod_cidlookup_shutdown() */
 SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_cidlookup_shutdown)
 {
+	switch_xml_config_cleanup(instructions);
 	switch_event_unbind(&reload_xml_event);
 	return SWITCH_STATUS_SUCCESS;
 }