BigInt memory leak fix (issue #651)

Signed-off-by: Adam Knapp <adam.knapp@ericsson.com>

compiler2/Int.cc

@@ -290,6 +290,7 @@ int_val_t int_val_t::operator-(const int_val_t& right) const
       char *result_str = BN_bn2dec(result);
       Int result_ll = string2Int(result_str, Location());
       OPENSSL_free(result_str);
+      BN_free(result);
       return int_val_t(result_ll);
     } else {
       return int_val_t(result);
@@ -378,6 +379,7 @@ int_val_t int_val_t::operator/(const int_val_t& right) const
       char *result_str = BN_bn2dec(result);
       Int result_ll = string2Int(result_str, Location());
       OPENSSL_free(result_str);
+      BN_free(result);
       return int_val_t(result_ll);
     } else {
       if (right.is_native())

core/Integer.cc

@@ -1724,6 +1724,7 @@ int INTEGER::get_nof_digits()
       ++digits;
       BN_div_word(x, 10);
     }
+    BN_free(x);
   }
   return digits;
 }