tests: remove disable_module

This test is included in almost all other tests. Testing the make system
this way is kinda nonsensical.

tests/disable_module/Makefile

@@ -1,6 +0,0 @@
-APPLICATION = disable_module
-include ../Makefile.tests_common
-
-DISABLE_MODULE += auto_init
-
-include $(RIOTBASE)/Makefile.include

tests/disable_module/main.c

@@ -1,45 +0,0 @@
-/*
- * Copyright (C) 2014 René Kijewski <rene.kijewski@fu-berlin.de>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/**
- * @ingroup tests
- * @{
- *
- * @file
- * @brief    Test whether DISABLE_MODULE works.
- *
- * @author   René Kijewski <rene.kijewski@fu-berlin.de>
- *
- * @}
- */
-
-#include <stdio.h>
-
-int main(void)
-{
-    puts("Start.");
-
-#   ifdef MODULE_AUTO_INIT
-    puts("-ERROR: MODULE_AUTO_INIT present!");
-#   else
-    puts("+OK: MODULE_AUTO_INIT absent.");
-#   endif
-
-    puts("Done.");
-    return 0;
-}