Follow-up to r25355, add required cwd restore in merge_test-52.
Follow-up to r25355, add required cwd restore in merge_test-52.

* subversion/tests/cmdline/merge_tests.py
  (empty_rev_range_mergeinfo): Add required os.chdir(), since this test is
  XFail it's absence was probably never noticed.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@865433 13f79535-47bb-0310-9956-ffa450edef68

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