Remove path that got duplicated in the tests twice.

* subversion/tests/cmdline/basic_tests.py
  (special_paths_in_repos): No need to test '/C&' twice.

Found by: rhuijben


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1593812 13f79535-47bb-0310-9956-ffa450edef68