Update the way we handle is_single() to is_singular() in order to solve this topic issue : https://wordpress.org/support/topic/single-post-or-page?replies=3#post-6208830

git-svn-id: https://plugins.svn.wordpress.org/olalaweb-mailchimp-campaign-manager/trunk@1023217 b8457f37-d9ea-0310-8a92-e5e31aec5664