net: fix a typo

Change-Id: I29fadde646095fa8507f239a339857bf53172c14
Reviewed-on: https://go-review.googlesource.com/27418Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/dnsclient_unix_test.go

@@ -411,7 +411,7 @@ func TestGoLookupIPWithResolverConfig(t *testing.T) {
 			// We need to take care with errors on both
 			// DNS message exchange layer and DNS
 			// transport layer because goLookupIP may fail
-			// when the IP connectivty on node under test
+			// when the IP connectivity on node under test
 			// gets lost during its run.
 			if err, ok := err.(*DNSError); !ok || tt.error != nil && (err.Name != tt.error.(*DNSError).Name || err.Server != tt.error.(*DNSError).Server || err.IsTimeout != tt.error.(*DNSError).IsTimeout) {
 				t.Errorf("got %v; want %v", err, tt.error)