use osmo_sockaddr_str_is_nonzero()

Also regard an RTP port as invalid if the IP address is 0.0.0.0.
Achieve this by using osmo_sockaddr_str_is_nonzero() instead of
osmo_sockaddr_str_is_set().

Depends: I73cbcab90cffcdc9a5f8d5281c57c1f87b2c3550 (libosmocore)
Change-Id: I53ddb19a70fda3deb906464e1b89c12d9b4c7cbd
diff --git a/src/libmsc/msc_ho.c b/src/libmsc/msc_ho.c
index 615b8cd..99f37b6 100644
--- a/src/libmsc/msc_ho.c
+++ b/src/libmsc/msc_ho.c
@@ -661,7 +661,7 @@
 	}
 
 	msc_a->ho.new_cell.ran_remote_rtp = hra->ran_dec->handover_request_ack.remote_rtp;
-	if (osmo_sockaddr_str_is_set(&msc_a->ho.new_cell.ran_remote_rtp)) {
+	if (osmo_sockaddr_str_is_nonzero(&msc_a->ho.new_cell.ran_remote_rtp)) {
 		LOG_HO(msc_a, LOGL_DEBUG, "Request Ack contains cell's RTP address " OSMO_SOCKADDR_STR_FMT "\n",
 		       OSMO_SOCKADDR_STR_FMT_ARGS(&msc_a->ho.new_cell.ran_remote_rtp));
 	}
@@ -684,7 +684,7 @@
 		return;
 	}
 
-	if (!osmo_sockaddr_str_is_set(&msc_a->ho.new_cell.ran_remote_rtp)) {
+	if (!osmo_sockaddr_str_is_nonzero(&msc_a->ho.new_cell.ran_remote_rtp)) {
 		LOG_HO(msc_a, LOGL_DEBUG, "New cell's RTP IP:port not yet known, not switching RTP stream\n");
 		return;
 	}
@@ -738,7 +738,7 @@
 		return;
 	}
 
-	if (!osmo_sockaddr_str_is_set(&msc_a->ho.old_cell.ran_remote_rtp)) {
+	if (!osmo_sockaddr_str_is_nonzero(&msc_a->ho.old_cell.ran_remote_rtp)) {
 		LOG_HO(msc_a, LOGL_DEBUG, "Have no RTP IP:port for the old cell, not switching back to\n");
 		return;
 	}