doubleSizeIfRetina should be called in all +WebCache methods that receive a size

[gtg922r]

"doubleSizeIfRetina" was added for some methods, but not for:

- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options andResize:(CGSize)size

and

- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options andResize:(CGSize)size

Since these methods are called by the shorter methods (without placeholder image), just move the doubleSizeIfRetina call to these methods.