bliss: Remove unnecessary cast to double

Coverity is still not happy when the result of an integer division is
assigned to a double (without e.g. casting the result to an int first to
indicate the intent).  The shift should avoid this issue.

src/libstrongswan/plugins/bliss/bliss_huffman.c

@@ -276,7 +276,7 @@ int main(int argc, char *argv[])
 	/* Probability distribution for z2 */
 	dx = 1 << set->d;
 	k_top = 1 + set->B_inf / dx;
-	x = (double)(dx/2) - 0.5;
+	x = (dx >> 1) - 0.5;
 	p_sum = 0;
 
 	for (k = 0; k < k_top; k++)