[ACS42]CLOUDSTACK-4456,CLOUDSTACK-4456,CLOUDSTACK-4456

[Edison Su]

Need to apply a0de0d0177a9251756d57ebdbea93f51a597ac1f and 
d157e2970ebd6d8d4c5a98a6d2adbc5da013f59b on 4.2
During the automation test, sometimes, KVM can't find volume, so add the code 
to look up volume for a few times(refresh storage pool).