fix test_update_slaves_on_cbt_disable

Signed-off-by: Ronan Abhamon <ronan.abhamon@vates.tech>

Author: Wescoeur

tests/test_LVMSR.py

@@ -588,6 +588,28 @@ def test_update_slaves_on_cbt_disable(self, mock_xenapi, mock_lock):
         sr = self.create_LVMSR()
         sr.isMaster = True
 
+        self.mock_sr_util.pathexists.side_effect = [
+            False,
+            False,
+            False, # AIO
+            True,  # VHD
+            False, # QCOW2
+            False,
+            True,
+            True,
+            False,
+            False, # AIO
+            True,  # VHD
+            False, # QCOW2
+            False,
+            True,
+            False,
+            True,
+            False,
+            True,
+            False
+        ]
+
         vdi = sr.vdi(vdi_uuid)
         vdi.vdi_type = vhdutil.VDI_TYPE_VHD