builtin-extensions: remove usage of org.ovirt.engine.core.utils.log.Log

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1109871
Change-Id: I43124cb57f54c60f6e8717678a87f151bccdf856
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>