Use correct SSH keys metadata for GCE provisioning. (StreisandEffect#…

…1048)

Per the GCE docs on SSH metadata[0]:
> Note: Setting the sshKeys metadata value on project metadata is
> deprecated. Use the ssh-keys metadata value instead. If instances in
> your project uses older images, you might need to update the guest
> environments for these instances.

This commit updates the metadata key to be "ssh-keys" instead of
"sshKeys", fixing the problem where GCE provisioning required manual
intervention to fix SSH access.

[0] - https://cloud.google.com/compute/docs/instances/adding-removing-ssh-keys

playbooks/roles/genesis-google/tasks/main.yml

@@ -18,7 +18,7 @@
     service_account_email: "{{ gce_service_account_email }}"
     image: "{{ gce_image }}"
     tags: "{{ gce_server_name }}"
-    metadata: '{"sshKeys":"root:{{ ssh_key.stdout }}"}'
+    metadata: '{"ssh-keys":"ubuntu:{{ ssh_key.stdout }}"}'
   register: streisand_server
 
 - name: Wait until the server has finished booting and OpenSSH is accepting connections