Rename baton structs in the repos-wc diff editor to include our common _t
suffix. No functional changes.

* subversion/libsvn_wc/diff_editor.c
  (*): Rename struct references.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1444747 13f79535-47bb-0310-9956-ffa450edef68