CLOUDSTACK-4495: systemVM template URL is pointing to old template location in upgrade file.

SystemVM template URL for XenServer hypervisor is pointing to old template location in the Upgrade410to420.java  file.
CLOUDSTACK-4492: DB upgrade for volume state, from UploadOp to Uploaded
CLOUDSTACK-3405: execute.in.sequence.hypervisor.commands and
execute.in.sequence.network.element.commands should be set to "true" by
default.