Make logger imports and function conditional

Silences -Wall for unused imports/function if PRODUCTION is defined

yesod/scaffold/main.hs.cg

@@ -5,10 +5,12 @@ import Application (with~sitearg~)
 import Network.Wai.Handler.Warp (run)
 import System.Console.CmdArgs hiding (args)
 import Data.Char (toUpper, toLower)
-import Yesod.Logger (logString, logLazyText, flushLogger, makeLogger)
 
 #ifndef PRODUCTION
 import Network.Wai.Middleware.Debug (debugHandle)
+import Yesod.Logger (logString, logLazyText, flushLogger, makeLogger)
+#else
+import Yesod.Logger (makeLogger)
 #endif
 
 main :: IO ()
@@ -24,9 +26,9 @@ main = do
     logString logger $ (show env) ++ " application launched, listening on port " ++ show (appPort c)
     with~sitearg~ c logger $ run (appPort c) . debugHandle (logHandle logger)
     flushLogger logger
-#endif
   where
     logHandle logger msg = logLazyText logger msg >> flushLogger logger
+#endif
 
 data ArgConfig = ArgConfig {environment :: String, port :: Int}
                  deriving (Show, Data, Typeable)