Remove a useless optimization

This optimization is aimed at old hardware only (withouth popcount), and even on
non popcount compile (ARCH=x86-64), it provides no mesurable speedup:

stat        test     master     diff
mean   2,341,779  2,354,699  -12,920
stdev     12,910     14,770   18,150

speedup      -0.55%
P(speedup>0)  23.8%

No functional change.

Resolves #187

src/evaluate.cpp

@@ -534,7 +534,7 @@ namespace {
 
         b = weak & ~ei.attackedBy[Them][ALL_PIECES];
         if (b)
-            score += more_than_one(b) ? Hanging * popcount<Max15>(b) : Hanging;
+            score += Hanging * popcount<Max15>(b);
 
         b = weak & ei.attackedBy[Us][KING];
         if (b)