Rename 1.3.x-r17280-r18172 branch to 1.3.x-r17280-r18172-r18205, to reflect
the fact that this branch will soon contain r18205.



git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.3.x-r17280-r18172-r18205@858280 13f79535-47bb-0310-9956-ffa450edef68