socket: Plug resource leak when the listen call is failing.
diff --git a/openbsc/src/socket.c b/openbsc/src/socket.c
index d60c43e..b430cf7 100644
--- a/openbsc/src/socket.c
+++ b/openbsc/src/socket.c
@@ -94,6 +94,7 @@
 		ret = listen(bfd->fd, 1);
 		if (ret < 0) {
 			perror("listen");
+			close(bfd->fd);
 			return ret;
 		}
 	}