Opening 1.8.x backport branch for r1564215.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1564215@1564281 13f79535-47bb-0310-9956-ffa450edef68
On the 1.8.x-r1564215 branch: Merge r1564215 from trunk and
resolve the text conflicts.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1564215@1564361 13f79535-47bb-0310-9956-ffa450edef68
Merge the 1.8.x-r1564215 branch:

 * r1564215
   Reduce dynamic memory usage during c/o and export.
   Branch: ^/subversion/branches/1.8.x-r1564215
   Justification:
     Without this patch, operations using the standard reporter (at least
     svn: c/o and export; probably same for httpv1) use more or less
     unbounded amounts of memory.  Dynamic peaks of up to 20GB have been
     observed.  With this patch, those peaks come down to 100MB which
     matches our claim to streaminess.
   Votes:
     +1: stefan2, philip, breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1564621 13f79535-47bb-0310-9956-ffa450edef68
Merge the r1534149 group from trunk:

 * r1534149, r1535676
   In the windows CryptoAPI ssl certificate verification, properly handle
   certificates that are only trusted via intermediate authorities.
   Justification:
      While not strictly a bug, intermediate authorities are getting more
      common since recent Certificate Authority incidents.
   Notes:
      rhuijben: This introduces a new credential type as private API.
      Not sure about our strict ABI guarantees here, but this affects
      usability of users migrating to cloud platforms, etc.
   Votes:
     +1: rhuijben, steveking, breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1564623 13f79535-47bb-0310-9956-ffa450edef68