engine: Enable Long xmlrpc support for new VM and disk hotplug

This is needed for the two commands to support Long based
values in the ioTune QoS policy parameters.

Change-Id: I82673b6dec7ba320c56a1cf6e0cd3f1dde86fd22
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1145621
Signed-off-by: Martin Sivak <msivak@redhat.com>