MT#55283 prevent erroneous swithch to DB 0

A call that gets created but then doesn't get initialised would have its
Redis DB left at zero. At destruction it would then try to switch to DB
zero. Fix this by using an appropriate initial value.

Closes #1905

Change-Id: I852e48c5a06b732b37d2ccd5c478de4760aacd4e
(cherry picked from commit add46f265a)

daemon/call.c

@@ -4067,6 +4067,7 @@ static call_t *call_create(const str *callid) {
 	c->dtls_cert = dtls_cert();
 	c->tos = rtpe_config.default_tos;
 	c->poller = rtpe_get_poller();
+	c->redis_hosted_db = -1;
 	if (rtpe_config.cpu_affinity)
 		c->cpu_affinity = call_socket_cpu_affinity++ % rtpe_config.cpu_affinity;
 	else

include/call.h

@@ -767,7 +767,7 @@ struct call {
 	sockaddr_t		xmlrpc_callback;
 	endpoint_t		dtmf_log_dest;
 
-	unsigned int		redis_hosted_db;
+	int			redis_hosted_db;
 	atomic64		last_redis_update;
 
 	struct recording 	*recording;