tests: Fix skipping mkdir-with-parents-permission test

If the user has `CAP_DAC_OVERRIDE` or similar (for example, if running
the tests as root), the `mkdir-with-parents-permission` test is skipped.

The check for `CAP_DAC_OVERRIDE` was by creating a subdirectory of the
test directory. That subdirectory, however, was never removed, which
caused a ‘directory not empty’ error when trying to delete the test
directory.

Fix that by correctly deleting the subdirectory if skipping the test.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

glib/tests/fileutils.c

@@ -548,6 +548,7 @@ test_mkdir_with_parents_permission (void)
   if (g_mkdir (subdir2, 0700) == 0)
     {
       g_test_skip ("have CAP_DAC_OVERRIDE or equivalent, cannot test");
+      g_remove (subdir2);
     }
   else
     {