OS/390: install apachecore.[dll|x] in lib/ rather than bin/ .

The LIBPATH env var already must contain the path to lib/ in order to pick up
apr and apr-util.  If we install the core dll there as well, LIBPATH becomes
simpler.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94053 13f79535-47bb-0310-9956-ffa450edef68