dns resolver: reorder sockaddr union to make initialization safe

some recent compilers have adopted a dubious interpretation of the C
specification for union initializers, that when the initialized member
is smaller than the size of the union, the remaining padding does not
have to be zero-initialized. in the interests of not depending on any
particular interpretation, place the larger member first so it's
initialized and ensures the whole object is zero-filled.

src/network/res_msend.c

@@ -83,8 +83,8 @@ int __res_msend_rc(int nqueries, const unsigned char *const *queries,
 	int fd;
 	int timeout, attempts, retry_interval, servfail_retry;
 	union {
-		struct sockaddr_in sin;
 		struct sockaddr_in6 sin6;
+		struct sockaddr_in sin;
 	} sa = {0}, ns[MAXNS] = {{0}};
 	socklen_t sl = sizeof sa.sin;
 	int nns = 0;