Merge the 1.9.x-r1808955 branch:

 * r1808955, r1808956, r1809558, r1809564
   Transmit the run-time HTTPD version to the DAV test driver.
   Justification:
     Prevents spurious test failures where compile-time and run-time
     HTTPD versions are different.
   Branch:
     ^/subversion/branches/1.9.x-r1808955
   Votes:
     +1: brane, stefan2
     +0: danielsh (this works on OS X and Linux but nevertheless I wonder
          about its portability)


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.9.x@1820523 13f79535-47bb-0310-9956-ffa450edef68