loplugin:redundantcast: tools

(after a to-be-committed improved loplugin:cstylecast would have rewritten the
C-style casts into static_casts)

Change-Id: I20c94335b3ddeeea40af1f2b0d3777f139186a01

include/tools/bigint.hxx

@@ -186,7 +186,7 @@ inline bool BigInt::IsNeg() const
     if ( !bIsBig )
         return (nVal < 0);
     else
-        return (bool)bIsNeg;
+        return bIsNeg;
 }
 
 inline bool BigInt::IsZero() const