[nominatim-web] Treat HEAD as GET

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 1ef0e16e8523ad482aa9f830cfe15e9d0f303874
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Wed May 27 12:16:36 2020 +0200

    Treat HEAD as GET

 redis.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/redis.lua b/redis.lua
index a444ecc..d9a3e18 100644
--- a/redis.lua
+++ b/redis.lua
@@ -10,7 +10,7 @@ if not ok then
     ngx.exit(ngx.HTTP_SERVICE_UNAVAILABLE)
 end
 
-if method == "GET" then
+if method == "GET" or method == "HEAD" then
     local res, err = red:get(key)
 
     if err then