This adds search domain support by trying to resolve a name by
appending each search domain configured in /etc/resolv.conf until
the query succeeds (NOERROR) and has at least one answer.
Change-Id: Ibdc5138c5d8cc049e11fab90c3d5243d5a06852c
This reverts commit e3bc6fc9dc, reversing
changes made to 1cf9e5840a.
Conflicts:
retrieval/target_provider.go
Change-Id: Icb6e98fb30419e9e2fe9b686c243702ced372014