Checksum download is unnecessary when using local binary (#45)

Author: Cornelicorn

tasks/preflight.yml

@@ -18,3 +18,4 @@
   set_fact:
     coredns_checksum: "{{ lookup('url', 'https://github.com/coredns/coredns/releases/download/v' + coredns_version + '/coredns_' + coredns_version + '_linux_' + go_arch + '.tgz.sha256').split(' ')[0] }}"
   run_once: true
+  when: coredns_binary_local_dir | length == 0