fix some issue when adding tags to post

git-svn-id: https://plugins.svn.wordpress.org/polylang/trunk@784691 b8457f37-d9ea-0310-8a92-e5e31aec5664
release v1.1.6

git-svn-id: https://plugins.svn.wordpress.org/polylang/trunk@787313 b8457f37-d9ea-0310-8a92-e5e31aec5664