cmd/golangorg: disable IP-based China detection

The IP-based detection of requests from China is from back in 2015
when we were preparing to serve golang.org directly in China.
In 2018 we arranged to use golang.google.cn instead,
but the old IP-based detection has lingered.
It is no longer required, and it has false positives, so remove it.

Fixes golang/go#47808.

Change-Id: Ia7854456f8c0614c55007688e65c3c62c1799f33
Reviewed-on: https://go-review.googlesource.com/c/website/+/344289
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Website-Publish: Russ Cox <rsc@golang.org>
diff --git a/cmd/golangorg/googlecn.go b/cmd/golangorg/googlecn.go
index d1dbb8c..5bf21a3 100644
--- a/cmd/golangorg/googlecn.go
+++ b/cmd/golangorg/googlecn.go
@@ -11,18 +11,7 @@
 
 // googleCN reports whether request r is considered to be arriving from China.
 // Typically that means the request is for host golang.google.cn,
-// but we also report true for requests that set googlecn=1 as a query parameter
-// and for requests that App Engine geolocates in China.
+// but we also report true for requests that set googlecn=1 as a query parameter.
 func googleCN(r *http.Request) bool {
-	if r.FormValue("googlecn") != "" {
-		return true
-	}
-	if strings.HasSuffix(r.Host, ".cn") {
-		return true
-	}
-	switch r.Header.Get("X-Appengine-Country") {
-	case "CN":
-		return true
-	}
-	return false
+	return r.FormValue("googlecn") != "" || strings.HasSuffix(r.Host, ".cn")
 }