On the 1.8.x-r1469519-and-friends branch: fix merge-info oops from r1482494.

r1482494 should have left merge-info on configure.ac to indicate that
it didn't get r1481848 merged into it.  Fix this with:

$ svn merge -c -1481848 --record-only https://svn.apache.org/repos/asf/subversion/trunk/configure.ac configure.ac


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1469519-and-friends@1482519 13f79535-47bb-0310-9956-ffa450edef68