This reverts commit 33ea0a3c5b.
Historical note: unbound was added to the base job originally with
Ifeade0e5e9566d8b5e83569b598610e9af12c2c9 but then reverted with
I77b2b2e7f5df4cab5a937b5b8bc47a7eef7b6977.
It turns out hosts without ipv6 failed to be detected. This was
addressed with I96b0fd98db01b183946403a744ff2e8d2ae422d8.
Results for base-test runs with this change can be seen in
I43373c12766c95573367262b9e24beb8ef6b8098.
Change-Id: I8479c40fa72e9c06fa717cb4ad3ab88ca7bdc847
c06274ce33