app.yaml: remove GOLANGORG_CHECK_COUNTRY

Nothing in this package or its dependencies uses this variable,
after CL 293449.

Change-Id: I5abb409616bdbe991bb2cbb0014c358090b197f7
Reviewed-on: https://go-review.googlesource.com/c/blog/+/295213
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>
diff --git a/app.yaml b/app.yaml
index 3d0f8c1..b2aac6e 100644
--- a/app.yaml
+++ b/app.yaml
@@ -2,7 +2,6 @@
 runtime: go114
 
 env_variables:
-  GOLANGORG_CHECK_COUNTRY: true
   BLOG_ANALYTICS: |
     <script async src="https://www.googletagmanager.com/gtag/js?id=UA-11222381-3"></script>
     <script>