If golang-doc is not present, the start page for godoc does not contain the
text expected in tests.

--- a/cmd/godoc/godoc_test.go
+++ b/cmd/godoc/godoc_test.go
@@ -224,7 +224,7 @@
 	}{
 		{
 			path:  "/",
-			match: []string{"Go is an open source programming language"},
+			match: []string{"The Go Programming Language"},
 		},
 		{
 			path:  "/pkg/fmt/",