Disable tests that rely on usable DNS lookups, which aren't available
in build chroots.

--- libevent-2.0.21-stable/test/regress_dns.c	2013-01-20 22:32:09.000000000 +0100
+++ libevent-2.0.21-stable/test/regress_dns.c	2013-01-20 22:32:30.000000000 +0100
@@ -2120,10 +2120,6 @@
 
 struct testcase_t dns_testcases[] = {
 	DNS_LEGACY(server, TT_FORK|TT_NEED_BASE),
-	DNS_LEGACY(gethostbyname, TT_FORK|TT_NEED_BASE|TT_NEED_DNS|TT_OFF_BY_DEFAULT),
-	DNS_LEGACY(gethostbyname6, TT_FORK|TT_NEED_BASE|TT_NEED_DNS|TT_OFF_BY_DEFAULT),
-	DNS_LEGACY(gethostbyaddr, TT_FORK|TT_NEED_BASE|TT_NEED_DNS|TT_OFF_BY_DEFAULT),
-	{ "resolve_reverse", dns_resolve_reverse, TT_FORK|TT_OFF_BY_DEFAULT, NULL, NULL },
 	{ "search_empty", dns_search_empty_test, TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
 	{ "search", dns_search_test, TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
 	{ "search_lower", dns_search_lower_test, TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
@@ -2163,9 +2159,6 @@
 
 	{ "client_fail_requests", dns_client_fail_requests_test,
 	  TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
-	{ "client_fail_requests_getaddrinfo",
-	  dns_client_fail_requests_getaddrinfo_test,
-	  TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
 
 	END_OF_TESTCASES
 };
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