sms_queue: Make deletion of messages from DB VTY-configurable

This introduces some VTY settings that determine if delivered
or expired messages should be removed from he SQL database or not.

Change-Id: Id6174875d5c01c40d987077651b27ae1acbcaa93
diff --git a/include/osmocom/msc/sms_queue.h b/include/osmocom/msc/sms_queue.h
index 76f885b..ccc56ab 100644
--- a/include/osmocom/msc/sms_queue.h
+++ b/include/osmocom/msc/sms_queue.h
@@ -1,6 +1,8 @@
 #ifndef SMS_QUEUE_H
 #define SMS_QUEUE_H
 
+#include <stdbool.h>
+
 struct gsm_network;
 struct gsm_sms_queue;
 struct vty;
@@ -9,6 +11,8 @@
 	char *db_file_path;			/* SMS database file path */
 	int max_fail;				/* maximum number of delivery failures */
 	int max_pending;			/* maximum number of gsm_sms_pending in RAM */
+	bool delete_delivered;			/* delete delivered SMS from DB? */
+	bool delete_expired;			/* delete expired SMS from DB? */
 };
 
 struct sms_queue_config *sms_queue_cfg_alloc(void *ctx);