Fix for installing repo-server with limit

This fix will help in installing repo container limiting
to nodes

Closes-Bug: 1659962
Change-Id: I0e50e2b1861fa7944aebfefcbcbee58207426a00

tasks/repo_key_distribute.yml

@@ -18,6 +18,7 @@
     user: "{{ repo_service_user_name }}"
     key: "{{ hostvars[item]['repo_pubkey'] | b64decode }}"
   with_items: "{{ groups['repo_all'] }}"
+  when: hostvars[item]['repo_pubkey'] is defined
   tags:
     - repo-key
     - repo-key-store