core: support adding template version

This patch add the ability to specify on add template,
that this will be version of a template.

http://www.ovirt.org/index.php?title=Features/Template_Versions

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1037478
Change-Id: Id256ade6e3973d5ad00daa267f80e5ce42b87872
Signed-off-by: Omer Frenkel <ofrenkel@redhat.com>