Revert it part r1783317, 'avoid _free()ing NULL references.'

OpenSSL team is committed to preserving safe _free(NULL) behaviors, and the
overhead of these calls in the context setup path is inconsequential. 



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1783434 13f79535-47bb-0310-9956-ffa450edef68