gitignore: Ingore vdsm-lvm.rule.tpl

In a previous commit I forgot to add this new template to the ignore
list, which breaks the build. I will be punished for this.

Change-Id: Ibc30423f6f47a6d8eb0326d94f6ce69ce3cdd5f1
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/33630
Reviewed-by: Dan Kenigsberg <danken@redhat.com>