app: remove HK and RC from share-blocked country code list

These codes were initially included because of a miscommunication.
They should not be in the list at all.

Fixes golang/go#12747

Change-Id: I864cff022a8996d672d9d88e0a9a1d76ba9bc54a
Reviewed-on: https://go-review.googlesource.com/15083
Reviewed-by: Minux Ma <minux@golang.org>
diff --git a/app/goplay/share.go b/app/goplay/share.go
index cce9e2a..72fca10 100644
--- a/app/goplay/share.go
+++ b/app/goplay/share.go
@@ -76,7 +76,7 @@
 		return true
 	}
 	switch r.Header.Get("X-AppEngine-Country") {
-	case "", "ZZ", "HK", "CN", "RC":
+	case "", "ZZ", "CN":
 		return false
 	}
 	return true