core: Fix scoreboard crash (SIGBUS) on hardware requiring strict 64bit

alignment (SPARC64, PPC64).
Submitted by: ylavic
Reviewed by: jim, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1712294 13f79535-47bb-0310-9956-ffa450edef68