Refactor testsuite test data dir create/populate, add djbdns

Now always wipes out the specific testout dir, and creates
  and populates the etc/zones and etc/djbdns directories iff
  they exist for the test
add etc/djbdns to list of paths created in chroot-mode
Very basic djbdns test

Just to serve as a test of testing, feel free to delete when
  replacing with better tests.