Simplify condition for ThreatByRook

Remove stronglyProtected Queen for ThreatByRook. Idea is that in the
current master the  SliderOnQueen bonus and the see_ge() function do
something similar as ThreatByRook for Queen, so this patch removes
some redundancy, in that sense.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 21878 W: 4939 L: 4818 D: 12121
http://tests.stockfishchess.org/tests/view/5b53a83b0ebc5902bdb815d1

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 35307 W: 5979 L: 5882 D: 23446
http://tests.stockfishchess.org/tests/view/5b53b60b0ebc5902bdb8174c

Close #1690

Bench: 4834554

src/evaluate.cpp

@@ -542,7 +542,7 @@ namespace {
                 score += ThreatByRank * (int)relative_rank(Them, s);
         }
 
-        b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK];
+        b = weak & attackedBy[Us][ROOK];
         while (b)
         {
             Square s = pop_lsb(&b);
@@ -557,7 +557,7 @@ namespace {
 
         score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);
 
-        b =  weak & nonPawnEnemies & attackedBy[Them][ALL_PIECES];
+        b = weak & nonPawnEnemies & attackedBy[Them][ALL_PIECES];
         score += Overload * popcount(b);
     }