ansible-playbooks/general#85 Quoting some strings

defaults/main.yml

@@ -15,7 +15,7 @@ sd_groups:
   mysql: none
   proxy: none
 
-sd_repo_public_key_uri: https://archive.serverdensity.com/sd-packaging-public.key
+sd_repo_public_key_uri: 'https://archive.serverdensity.com/sd-packaging-public.key'
 sd_agent_plugins_dir: /usr/share/python/sd-agent/checks.d/plugins
 sd_plugins_files_dir: "{{ playbook_dir }}/files/sd-plugins"