r1364253 forces the build to find mod_ssl.h

This should be CTR, feel free to revert if you do 
not like this way of finding the required header.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1369191 13f79535-47bb-0310-9956-ffa450edef68