ab: print Server Temp Key information.

trunk patch: http://svn.apache.org/r1738415
             http://svn.apache.org/r1826930
2.4.x patch: https://svn.apache.org/repos/asf/httpd/httpd/patches/2.4.x/httpd-2.4-ab.patch
+1: minfrin, jim, ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1843411 13f79535-47bb-0310-9956-ffa450edef68