build: Fix ast_sockaddr initialization to be more portable

A change to glibc 2.22 changed the order of the sockadddr_storage
members which caused the places where we do an initialization of
ast_sockaddr with '{ { 0, 0, } }' to fail compilation.  Those
initializers (which we shouldn't have been using anyway) have been
replaced with memsets.

Change-Id: Idd1b3b320903d8771bfe221f0b015685de628fa4

channels/chan_sip.c

@@ -15790,11 +15790,12 @@ static void start_register_timeout(struct sip_registry *reg)
 
 static const char *sip_sanitized_host(const char *host)
 {
-	struct ast_sockaddr addr = { { 0, 0, }, };
+	struct ast_sockaddr addr;
 
 	/* peer/sip_pvt->tohost and sip_registry->hostname should never have a port
 	 * in them, so we use PARSE_PORT_FORBID here. If this lookup fails, we return
 	 * the original host which is most likely a host name and not an IP. */
+	memset(&addr, 0, sizeof(addr));
 	if (!ast_sockaddr_parse(&addr, host, PARSE_PORT_FORBID)) {
 		return host;
 	}

tests/test_netsock2.c

@@ -75,7 +75,7 @@ AST_TEST_DEFINE(parsing)
 	};
 
 	size_t x;
-	struct ast_sockaddr addr = { { 0, 0, } };
+	struct ast_sockaddr addr;
 	int parse_result;
 
 	switch (cmd) {
@@ -91,15 +91,17 @@ AST_TEST_DEFINE(parsing)
 	}
 
 	for (x = 0; x < ARRAY_LEN(test_vals); x++) {
+		memset(&addr, 0, sizeof(addr));
 		if ((parse_result = ast_sockaddr_parse(&addr, test_vals[x].address, 0)) != test_vals[x].expected_result) {
 			ast_test_status_update(test, "On '%s' expected %d but got %d\n", test_vals[x].address, test_vals[x].expected_result, parse_result);
 			res = AST_TEST_FAIL;
 		}
 		if (parse_result) {
-			struct ast_sockaddr tmp_addr = { { 0, 0, } };
+			struct ast_sockaddr tmp_addr;
 			const char *tmp;
 
 			tmp = ast_sockaddr_stringify(&addr);
+			memset(&tmp_addr, 0, sizeof(tmp_addr));
 			ast_sockaddr_parse(&tmp_addr, tmp, 0);
 			if (ast_sockaddr_cmp_addr(&addr, &tmp_addr)) {
 				char buf[64];