cmd/pkgsite: remove dcensus

Since the fetch code no longer records metrics, the pkgsite command
doesn't need to talk to OpenCensus.

For golang/go#48010

Change-Id: I2793046725cd8c66ddfb585370ba2bf4890a9366
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/346810
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/cmd/pkgsite/main.go b/cmd/pkgsite/main.go
index 0a6d2ba..3aa7d41 100644
--- a/cmd/pkgsite/main.go
+++ b/cmd/pkgsite/main.go
@@ -39,7 +39,6 @@
 
 	"github.com/google/safehtml/template"
 	"golang.org/x/pkgsite/internal"
-	"golang.org/x/pkgsite/internal/dcensus"
 	"golang.org/x/pkgsite/internal/fetch"
 	"golang.org/x/pkgsite/internal/fetchdatasource"
 	"golang.org/x/pkgsite/internal/frontend"
@@ -112,7 +111,7 @@
 	if err != nil {
 		die("%s\nMaybe you need to provide the location of static assets with -static.", err)
 	}
-	router := dcensus.NewRouter(frontend.TagRoute)
+	router := http.NewServeMux()
 	server.Install(router.Handle, nil, nil)
 	mw := middleware.Timeout(54 * time.Second)
 	log.Infof(ctx, "Listening on addr %s", *httpAddr)