lxc-oracle: only create media repo when --baseurl is specified

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxc-oracle: use db_load from container

This makes it so that the host doesn't need to have an old, compat
version of db43_load installed by using the db_load from the just
installed container. Some newer distributions do not even have an old
enough compat-db4 package available.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>