Remove static NS resolution from seed image

Seed VM is getting NS resolution from its DHCP lease given by libvirt. There is no need for manually specifying resolv.conf.
Besides, these two files were having bad filenames (.conf suffix) preventing them to by executed by dib-run-parts script
(see dib-run-parts regex : allowed_regex=${RUN_PARTS_REGEX:-"^[0-9A-Za-z_-]+$"} )

Change-Id: Ic12ff9d1a8a14fdab686288cac3b3ae23375ddf0