Use apr_pool_cleanup_register() to cleanup mc
Use apr_pool_cleanup_register() to cleanup mc

Instead of using apr_pool_userdata_set() since we don't use apr_pool_userdata_get() with the mag_conn_ptr apr_pool_cleanup_register() seem cleaner.

Reviewed-by: Simo Sorce <65f99581a93cf30dafc32b5c178edc6b0294a07f@redhat.com>

uhd-urz/mod_auth_gssapi,uhd-urz/mod_auth_gssapi,devurandom/mod_auth_gssapi,uhd-urz/mod_auth_gssapi,devurandom/mod_auth_gssapi,frenche/mod_auth_gssapi,frenche/mod_auth_gssapi,davisd123/mod_auth_gssapi,devurandom/mod_auth_gssapi,davisd123/mod_auth_gssapi,frenche/mod_auth_gssapi,davisd123/mod_auth_gssapi,frenche/mod_auth_gssapi