[Fixed] improper operation of the 'Delete revisions on initial publication' feature

- Now the copy revision is not to be removed.

git-svn-id: https://plugins.svn.wordpress.org/thin-out-revisions/trunk@765550 b8457f37-d9ea-0310-8a92-e5e31aec5664
Version 1.3.6

git-svn-id: https://plugins.svn.wordpress.org/thin-out-revisions/trunk@765551 b8457f37-d9ea-0310-8a92-e5e31aec5664