variables should not be substituted in message

Using $priority meant it would be substituted with the value of the
parameter when it should be shown as static text.

manifests/resource/location.pp

@@ -132,10 +132,10 @@ define nginx::resource::location (
 
   validate_array($index_files)
   if !is_integer($priority) {
-    fail("$priority must be an integer.")
+    fail('$priority must be an integer.')
   }
   if ($priority < 401) or ($priority > 599) {
-    fail("$priority must be in the range 401-599. It was set to ${priority}.")
+    fail('$priority must be in the range 401-599.')
   }
 
   # # Shared Variables