Fix unit test failure (apache#9238)

Author: vishesh92

plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/resource/wrapper/LibvirtConvertInstanceCommandWrapperTest.java

@@ -215,6 +215,7 @@ public void testGetUnmanagedInstanceDisks() {
 
         LibvirtDomainXMLParser parser = Mockito.mock(LibvirtDomainXMLParser.class);
         Mockito.when(parser.getDisks()).thenReturn(List.of(diskDef));
+        Mockito.doReturn(new Pair<String, String>(null, null)).when(convertInstanceCommandWrapper).getNfsStoragePoolHostAndPath(destinationPool);
 
         List<UnmanagedInstanceTO.Disk> unmanagedInstanceDisks = convertInstanceCommandWrapper.getUnmanagedInstanceDisks(disks, parser);
         Assert.assertEquals(1, unmanagedInstanceDisks.size());