Remove msCleanupOnSignal log messages (#5254)

Author: tbonfort

mapserv.c

@@ -52,7 +52,9 @@ void msCleanupOnSignal( int nInData )
   /* from within the signal handler on Unix.  So we force output through */
   /* normal stdio functions. */
   msIO_installHandlers( NULL, NULL, NULL );
+#ifndef NDEBUG
   msIO_fprintf( stderr, "In msCleanupOnSignal.\n" );
+#endif
   msCleanup();
   exit(0);
 }