I wouldn't, simply because adding more water once fermentation is over seems to me like an easy way to add oxygen or cause other issues. IMO, it's better to leave it and then figure out what you need to adjust for the next batch.
You'll have a crisper finish with a FG of 1.011 than you would have had at 1.017. IMO, that's a good thing as it makes for a quaffable brew. Although, with your starting gravity, you might be getting into imperial blonde ale territory