Remove unused get_md5

It's unused and it will be removed in Ansible 9.x

Change-Id: I66b314c9d71084f4636aa50c62ef8a216979e5e5

CONTRIBUTING.rst

@@ -90,7 +90,6 @@ when contributing code.
       - name: "Stat file for x reason"
         stat:
           file: '/path/to/file'
-          get_md5: no
 
 4. Playbook conditionals utilizing variables intended as booleans,
    should make use of the ``| bool`` casting feature.  This is due

playbooks/roles/bifrost-ironic-install/tasks/create_tftpboot.yml

@@ -128,7 +128,6 @@
     - name: "Check if the iPXE EFI image is present"
       stat:
         path: "{{ ipxe_dir }}/{{ ipxe_efi_binary }}"
-        get_md5: false
       register: test_ipxe_efi_binary_path
       ignore_errors: true