[scaffold] use if-then-else instead of guards

While the guards solution was nice, it causes GHC to emit a
non-exhaustive pattern warning.

yesod/scaffold/Application.hs.cg

@@ -33,9 +33,9 @@ makeApplication conf logger = do
     app <- toWaiAppPlain foundation
     return $ logWare app
   where
-    (logWare, setLogger)
-        | development = (logCallbackDev (logBS setLogger), logger)
-        | production  = (logCallback    (logBS setLogger), toProduction logger)
+    setLogger = if development then logger else toProduction logger
+    logWare   = if development then logCallbackDev (logBS setLogger)
+                               else logCallback    (logBS setLogger)
 
 makeFoundation :: AppConfig DefaultEnv Extra -> Logger -> IO ~sitearg~
 makeFoundation conf setLogger = do

yesod/scaffold/Settings.hs.cg

@@ -54,9 +54,8 @@ staticRoot conf = [st|#{appRoot conf}/static|]
 -- user.
 
 widgetFile :: String -> Q Exp
-widgetFile
-    | development = Yesod.Default.Util.widgetFileReload
-    | production  = Yesod.Default.Util.widgetFileNoReload
+widgetFile = if development then Yesod.Default.Util.widgetFileReload
+                            else Yesod.Default.Util.widgetFileNoReload
 
 data Extra = Extra
     { extraCopyright :: Text

yesod/scaffold/Settings/StaticFiles.hs.cg

@@ -8,9 +8,8 @@ import Settings.Development
 
 -- | use this to create your static file serving site
 staticSite :: IO Static.Static
-staticSite
-    | development = Static.staticDevel staticDir
-    | production  = Static.static      staticDir
+staticSite = if development then Static.staticDevel staticDir
+                            else Static.static      staticDir
 
 -- | This generates easy references to files in the static directory at compile time,
 --   giving you compile-time verification that referenced files exist.