mpl: removed unused variable

Signed-off-by: João Mai <[email protected]>

Author: joaomai

src/mpl/src/SACoreHardMacro.cpp

@@ -113,7 +113,7 @@ void SACoreHardMacro::perturb()
   const float action_prob_1 = pos_swap_prob_;
   const float action_prob_2 = action_prob_1 + neg_swap_prob_;
   const float action_prob_3 = action_prob_2 + double_swap_prob_;
-  const float action_prob_4 = action_prob_3 + exchange_prob_;
+
   if (op <= action_prob_1) {
     action_id_ = 1;
     singleSeqSwap(true);  // Swap two macros in pos_seq_