fix warning

Found this warning when building in house for StyleFeed.

Values of type 'NSInteger' should not be used as format arguments; add an explicit cast to 'long' instead

This is the same pattern I used in SSShopSenseClient.m, for example, see:

https://github.com/PopSugar/ShopStyle-App/blob/wip_3.2/ShopStyle/ShopStyle/Classes/ShopSense/SSShopSenseClient.m#L921

@aprato let me know what you think.