Implement CRYPTO_set_locking_callback() for mod_ssl

PR:
Obtained from:
Submitted by:	Madhusudan Mathihalli <madhusudan_mathihalli@hp.com>
Reviewed by:	dougm


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@90612 13f79535-47bb-0310-9956-ffa450edef68