It's been a long time since I bottled, but I've always thought that cooling the priming sugar solution wasn't necessary. Since the volume of sugar solution (maybe a cup or so) is so small compared to the 5 gallons of beer the temperature of the beer+solution will stabilize very near the beer's original temp without affecting the yeast needed to carb. Just toss the sugar solution into the bottling bucket, rack in the beer (which mixes in the sugar) and go.