add domain_search wikimedia.org to terbium

this is to add wikimedia.org to the "search" option
in /etc/resolv.conf (done by base module),
so that people can just ssh to 'bast1001' from here

in reply to:

<Krinkle> Hm.. bast1001 is not visible from terbium?
<Krinkle> bast1001.wikimedia.org works but not plain bast1001,
          from tin "bast1001" works, though

Change-Id: I0610e0c8390484cf634bbae1f0ea04e7da6efc78