nat: Use ':' to separate the message and strerror
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index 411782c..a4c2d69 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -967,7 +967,7 @@
 
 	ret = bind(bfd->fd, (struct sockaddr *) &addr, sizeof(addr));
 	if (ret < 0) {
-		fprintf(stderr, "Could not bind the BSC socket %s\n",
+		fprintf(stderr, "Could not bind the BSC socket: %s\n",
 			strerror(errno));
 		return -EIO;
 	}