Fix unbounded memory usage in mod_authz_svn when SVNPathAuthz short_circuit
option is used.

* subversion/include/mod_dav_svn.h
  (dav_svn_split_uri2, dav_svn_get_repos_path2): New.
  (dav_svn_split_uri, dav_svn_get_repos_path): Update docstring.

* subversion/mod_authz_svn/mod_authz_svn.c
  (get_access_conf): Call dav_svn_get_repos_path2() instead of
   dav_svn_get_repos_path() passing SCRATCH_POOL as POOL parameter.

* subversion/mod_dav_svn/mod_dav_svn.c
  (dav_svn_get_repos_path): Rename to ...
  (dav_svn_get_repos_path2): ... this, adding POOL parameter and use it for
   all allocations.
  (dav_svn_get_repos_path): New, wraps dav_svn_get_repos_path2().

* subversion/mod_dav_svn/repos.c
  (dav_svn_split_uri): Rename to ...
  (dav_svn_split_uri2): ... this, adding POOL parameter and use it for
   all allocations.
  (dav_svn_split_uri): New, wraps dav_svn_split_uri2().

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1647887 13f79535-47bb-0310-9956-ffa450edef68