On the pin-externals branch, fix non-portable use of paths in regression test.
On the pin-externals branch, fix non-portable use of paths in regression test.

* subversion/tests/cmdline/externals_tests.py
  (copy_pin_externals): Use os.path.join(wc_dir, 'foo') instead of the
   non-portable idiom wc_dir + '/foo'. Not all platforms use a forward
   slash as path separator.


git-svn-id: 50c5f5df37af4354ae6e67714fc94b8d09273154@1655019 13f79535-47bb-0310-9956-ffa450edef68

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