Ensure resolv.conf is generated properly in labs images

When vmbuilder creates new images resolv.conf info is baked into
the image, making it datacenter specific. This change empties the
/etc/resolvconf/resolv.conf.d/original file in the image so that
dhclient's reconfiguration of resolv.conf will work properly.

Change-Id: I5d32813d31188fabf77bf0c55344353c9a66e69b
Merge "Ensure resolv.conf is generated properly in labs images" into production