go.talks: fix bad build tags as reported by vet

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12313043
diff --git a/2012/simple/webfront/main.go b/2012/simple/webfront/main.go
index 222c726..6034992 100644
--- a/2012/simple/webfront/main.go
+++ b/2012/simple/webfront/main.go
@@ -1,3 +1,8 @@
+// +build OMIT
+
+// This is a somewhat cut back version of webfront, available at
+// http://github.com/nf/webfront
+
 /*
 Copyright 2011 Google Inc.
 
@@ -14,11 +19,6 @@
 limitations under the License.
 */
 
-// This is a somewhat cut back version of webfront, available at
-// http://github.com/nf/webfront
-
-// +build OMIT
-
 /*
 webfront is an HTTP server and reverse proxy.
 
diff --git a/2012/simple/webfront/server_test.go b/2012/simple/webfront/server_test.go
index 16f6d8b..a153ec2 100644
--- a/2012/simple/webfront/server_test.go
+++ b/2012/simple/webfront/server_test.go
@@ -1,3 +1,5 @@
+// +build OMIT
+
 /*
 Copyright 2011 Google Inc.
 
@@ -14,8 +16,6 @@
 limitations under the License.
 */
 
-// +build OMIT
-
 package main
 
 import (
diff --git a/2012/zen/hello.go b/2012/zen/hello.go
index 780d633..645295a 100644
--- a/2012/zen/hello.go
+++ b/2012/zen/hello.go
@@ -1,4 +1,5 @@
 // +build OMIT
+
 package main
 
 import "fmt"