Improve the value we provide to delete_entry() in the repos reporter.
Improve the value we provide to delete_entry() in the repos reporter.

This is a general correctness improvement, but also fixes a couple of test
failures in the Ev2 shims.

Current number of Ev2 test failures: 11

* subversion/libsvn_repos/reporter.c
  (update_entry): If we can't find the deleted revision, attempt to find a
    suitable value to provide for delete_entry().


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1240654 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion