Remove cs_CZ locale

Better to use default en_US locale.

Change-Id: I14b0393832fc99c767a3b1b6d35601291d9d8cf8
diff --git a/billometer/server/single.yml b/billometer/server/single.yml
index be13be2..8152202 100644
--- a/billometer/server/single.yml
+++ b/billometer/server/single.yml
@@ -22,7 +22,7 @@
       database:
         billometer:
           encoding: UTF8
-          locale: cs_CZ
+          locale: en_US
           users:
           - name: billometer
             createdb: true