Follow-up to r1559767: Fix out-of-bounds array access.

* subversion/libsvn_delta/xdelta.c
  (compute_delta): Don't look for 64 byte matches if there are less
                   than 64 bytes left to process

Found by: philip

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1570141 13f79535-47bb-0310-9956-ffa450edef68
* subversion/libsvn_client/diff.c
  (diff_content_changed): Rename and reduce scope some variables. No
    functional changes.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1570144 13f79535-47bb-0310-9956-ffa450edef68