Change wording for BN_mod_exp_mont_consttime() entry

 Changes between 0.9.7g and 0.9.7h  [XX xxx XXXX]

  *) Make a new fixed-window mod_exp implementation the default for

     RSA, DSA, and DH private-key operations to mitigate the

     hyper-threading timing attacks pointed out by Colin Percival

     (http://www.daemonology.net/hyperthreading-considered-harmful/),

     and potential related attacks.

     RSA, DSA, and DH private-key operations so that the sequence of

     squares and multiplies and the memory access pattern are

     independent of the particular secret key.  This will mitigate

     cache-timing and potential related attacks.

     BN_mod_exp_mont_consttime() is the new exponentiation implementation,

     and this is automatically used by BN_mod_exp_mont() if the new flag