md: Fix getting bitmap location on latest kernels

The 'md/bitmap/location' file no longer exists in sysfs when the
bitmap is not set. The location of the "internal" bitmap is also
slightly differet now.

Author: vojtechtrefny

src/plugins/mdraid.c

@@ -1489,6 +1489,9 @@ gchar* bd_md_get_bitmap_location (const gchar *raid_spec, GError **error) {
     sys_path = g_strdup_printf ("/sys/class/block/%s/md/bitmap/location", raid_node);
     g_free (raid_node);
 
+    if (!g_file_test (sys_path, G_FILE_TEST_EXISTS))
+        return g_strdup ("none");
+
     success = g_file_get_contents (sys_path, &ret, NULL, error);
     if (!success) {
         /* error is already populated */

tests/mdraid_test.py

@@ -476,7 +476,7 @@ def test_set_bitmap_location(self):
             self.assertTrue(succ)
 
         loc = BlockDev.md_get_bitmap_location("bd_test_md")
-        self.assertEqual(loc, "+8")
+        self.assertIn(loc, ("+8", "+2"))
 
         succ = BlockDev.md_set_bitmap_location("bd_test_md", "none")
         self.assertTrue(succ)
@@ -488,7 +488,7 @@ def test_set_bitmap_location(self):
         self.assertTrue(succ)
 
         loc = BlockDev.md_get_bitmap_location("bd_test_md")
-        self.assertEqual(loc, "+8")
+        self.assertIn(loc, ("+8", "+2"))
 
         # test some different name specifications
         # (need to switch between internal and none because setting the same