Use tcberner's patch to fix build with recent svn

The subversion port was upgraded to version 1.9. devel/kdevplatform fails to
build against it.

Bring in the patch attached to the bug tracking system by Tobias C. Berner.
See #203843 for more information.

PR: 203843
Submitted by: Tobias C. Berner (tcberner@gmail.com) via Bug Tracking System
Approved by: rakuco (mentor)
Differential Revision: https://reviews.freebsd.org/D4003