Followup to r1618841, the old fast_memcpy() returned target+len but
the replacement memcpy() returns target.

* subversion/libsvn_delta/text_delta.c
  (patterning_copy): Adjust target after memcpy.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1640832 13f79535-47bb-0310-9956-ffa450edef68