subversion: security bump to version 1.7.19

Fixes:
CVE-2014-3580: mod_dav_svn DoS from invalid REPORT requests.
CVE-2014-8108: mod_dav_svn DoS from use of invalid transaction names.

Also add hash file.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>