Add new tests for log -c. All XFailing for now.
Add new tests for log -c. All XFailing for now.

* subversion/tests/cmdline/log_tests.py
  (log_single_change): test 'log -c 4 url'
  (log_changes_range): test 'log -c 2:5 url'
  (log_changes_list): test 'log -c 2,5,7 url'
  (test_list): run the new tests

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@865249 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion