remove spaces that break resulting yaml (DataDog#336)

Author: ckolos

templates/agent-conf.d/docker_daemon.yaml.erb

@@ -80,10 +80,10 @@ instances:
     ## Tagging
     ##
 <% if @tags and ! @tags.empty? -%>
-      tags:
+    tags:
   <%- Array(@tags).each do |tag| -%>
     <%- if tag != '' -%>
-          - <%= tag %>
+       - <%= tag %>
     <%- end -%>
   <%- end -%>
 <% end -%>