Remove cs_CZ locale

Better to use default en_US locale.

Change-Id: I14b0393832fc99c767a3b1b6d35601291d9d8cf8
diff --git a/graphite/server/single.yml b/graphite/server/single.yml
index 364877e..237c65d 100644
--- a/graphite/server/single.yml
+++ b/graphite/server/single.yml
@@ -29,7 +29,7 @@
       database:
         graphite:
           encoding: UTF8
-          locale: cs_CZ
+          locale: en_US
           users:
           - name: graphite
             password: ${_param:postgresql_graphite_password}