Merge r1612225 from trunk:

 * r1612225
   Ignore ENOTIMPL and EINCOMPLETE errors when tweaking temporary file
   permission bits on non-windows systems.
   Justification:
     These errors imply the underlying filesystem doesn't support
     permissions. svn_io_copy_perms handles these errors in the
     same way.
   Votes:
     +1: stsp, breser, rhuijben


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1617870 13f79535-47bb-0310-9956-ffa450edef68