Instead of evaluating the repos-global access settings from svnserve.conf
again and again, read it once and store the result in the respository_t.

* subversion/svnserve/server.h
  (repository_t): add members for repo-global access settings
  (get_access): drop

* subversion/svnserve/serve.c
  (get_access): new config reader utility
  (set_access): initialize new repository_t members
  (current_access
   send_mechs,
   auth,
   must_have_access): update / simplify using the new struct members
  (find_repos): ditto; initialize new struct members

* subversion/svnserve/cyrus_auth.c
  (cyrus_auth_request): update / simplify using the new struct members

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1530121 13f79535-47bb-0310-9956-ffa450edef68