Ignore vmdk files as well as other image types
Ignore vmdk files as well as other image types

Change-Id: I012b21181f1e54a1e4a3707b0fdf8c0afa6222c2

richliu/devstack,bswartz/devstack,Mahito/devstack,dtroyer/devstack,dtroyer/devstack,openstack-dev/devstack,noironetworks/devstack,nawawi/openstack,bswartz/devstack,bigswitch/devstack,nawawi/openstack,noironetworks/devstack,group-policy/devstack,Mahito/devstack,group-policy/devstack,openstack-dev/devstack,richliu/devstack,bigswitch/devstack