Remove superfluous newlines as per PHPCBF

exceptions/generic/MDRequiredConfigNotSet.php

@@ -5,7 +5,6 @@
  * Custom exception class for errors loading configuration information.
  */
 final class MDRequiredConfigNotSet extends Exception {
-
     /**
      * Error message.
      *
@@ -17,5 +16,4 @@ public function errorMessage() {
         return $errorMsg;
 
     }
-
 }