synch 2.4.x with trunk. When r1729208 has been backported in 2.4.x (see r1743576), a coment has been missed in the backport proposal and has never reached 2.4.x. Add it now, in order to synch a bit the 2 branches.
httpd/httpd/branches/2.4.x/modules/ssl/ssl_engine_io.c