Log Message:
Update subversion to 1.6.13, fix security problem.

Quote from release announce:

This is a bugfix release, part of the 1.6.x release series.  Of note, this
release includes a fix which addresses CVE-2010-3315, a security issue when
using 'SVNPathAuthz short_circuit'.  More information can be found here:
http://subversion.apache.org/security/CVE-2010-3315-advisory.txt

CHANGES:

Version 1.6.13
(01 Oct 2010, from /branches/1.6.x)
http://svn.apache.org/repos/asf/subversion/tags/1.6.13

  User-visible changes:
   * don't drop properties during foreign-repo merges (issue #3623)
   * improve auto-props failure error message (r961970)
   * improve error message for 403 status with ra_neon (r876615)
   * don't allow 'merge --reintegrate' for 2-url merges (r959004)
   * improve handling of missing fsfs.conf during hotcopy (r980811, -1449)
   * escape unsafe characters in a URL during export (issue #3683)
   * don't leak stale locks in FSFS (r959760)
   * better detect broken working copies during update over ra_neon (r979045)
   * fsfs: make rev files read-only (r981921)
   * properly canonicalize a URL (r984928, -31)
   * fix wc corruption with 'commit --depth=empty' (issue #3700)
   * permissions fixes when doing reintegrate merges (related to issue #3242)
   * fix mergeinfo miscalculation during 2-url merges (issue #3648)
   * fix error transmission problems in svnserve (r997457, -66)
   * fixed: record-only merges create self-referential mergeinfo (issue #3646)
   * fixed: 'SVNPathAuthz short_circuit' unsolicited read access (issue #3695)
   * make 'svnmucc propset' handle existing and non-existing URLs (r1000607)
   * add new 'propsetf' subcommand to svnmucc (r1000612)
   * emit a warning about copied dirs during ci with limited depth (r1002094)

  Developer-visible changes:
   * make ruby bindings compatible with Ruby 1.9 (r957507)
   * use the repos verify API in JavaHL (r948916)
   * teach ra_serf to parse md5 checksums with update editors (r979429)
   * let ra_serf work with current serf releases (r879757, r880320, r943796)