[BUG] fix off-by-one in path length in destroy_uxst_socket()

An off-by-one error was left in the computation of the unix socket path.
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index d8c0a90..24c435f 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -198,7 +198,7 @@
 
 	addr.sun_family = AF_UNIX;
 	strncpy(addr.sun_path, path, sizeof(addr.sun_path));
-	addr.sun_path[sizeof(addr.sun_path)] = 0;
+	addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
 	ret = connect(sock, (struct sockaddr *)&addr, sizeof(addr));
 	if (ret < 0 && errno == ECONNREFUSED) {
 		/* Connect failed: the socket still exists but is not used