add CHANGES entry

 Changes between 0.9.8l (?) and 0.9.8m (?)  [xx XXX xxxx]

  *) The code that handled flusing of data in SSL/TLS originally used the

     BIO_CTRL_INFO ctrl to see if any data was pending first. This caused

     the problem outlined in PR#1949. The fix suggested there however can

     trigger problems with buggy BIO_CTRL_WPENDING (e.g. some versions

     of Apache). So instead simplify the code to flush unconditionally.

     This should be fine since flushing with no data to flush is a no op.

     [Steve Henson]

  *) Handle TLS versions 2.0 and later properly and correctly use the

     highest version of TLS/SSL supported. Although TLS >= 2.0 is some way

     off ancient servers have a habit of sticking around for a while...