fix mock_vhdutil

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

Author: Wescoeur

tests/test_blktap2.py

@@ -494,7 +494,7 @@ def test_setup_cache_success_prt_td_present(self, mock_find_by_path, mock_launch
         mock_vdi.path = "prt_path"
 
         # Return some sizes (all the same here)
-        self.mock_vhdutil.getSizeVirt.return_value = 20 * 1024 * 1024
+        self.mock_vhdutil.return_value.getSizeVirt.return_value = 20 * 1024 * 1024
 
         prt_tapdisk = blktap2.Tapdisk(
             1457, 3, 'vhd', 'dummy', 1)
@@ -528,7 +528,7 @@ def test_setup_cache_success_no_prt_td_present(self, mock_find_by_path, mock_lau
         mock_vdi.path = "prt_path"
 
         # Return some sizes (all the same here)
-        self.mock_vhdutil.getSizeVirt.return_value = 20 * 1024 * 1024
+        self.mock_vhdutil.return_value.getSizeVirt.return_value = 20 * 1024 * 1024
 
         # No existing tapdisk paths
         mock_find_by_path.return_value = {}