Open 1.8.x backport branch for r1567985.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1567985@1568016 13f79535-47bb-0310-9956-ffa450edef68
Merge r1567985 from /trunk and resolve a trival text conflict.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1567985@1568018 13f79535-47bb-0310-9956-ffa450edef68
Follow-up to r1568018: actually commit the source change.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1567985@1568020 13f79535-47bb-0310-9956-ffa450edef68
Merge the 1.8.x-r1567985 branch:

 * r1567985
   Infinite loop in caching code on 32 bit platforms.
   Branch: ^/subversion/branches/1.8.x-r1567985
   Justification:
     This affects all threaded servers and gets more frequent when only small
     caches like the 16MB default have been configured.  Once a thread enters
     the infinite loop, all other threads in the same process will soon hang
     as well.
   Votes:
     +1: stefan2, breser, philip


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1568056 13f79535-47bb-0310-9956-ffa450edef68