Tweak allocated time per move

It seems better to give more time in middle game then
at the end.

Also Toga uses the same limit.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/search.cpp

@@ -436,7 +436,7 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
           MaxSearchTime = myTime / 30 + myIncrement;
           AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
       } else { // Blitz game without increment
-          MaxSearchTime = myTime / 40;
+          MaxSearchTime = myTime / 30;
           AbsoluteMaxSearchTime = myTime / 8;
       }
   }