R1:88189f723f05

Make a Feed query construction less clever/sneaky for new qsprintf() semantics

Summary:
Ref T13216. Ref T13217. Currently, we build this query in a weird way so we end up with `(1, 2, 3)` on both 32-bit and 64-bit systems.

I can't reproduce the string-vs-int MySQL key issue on any system I have access to, so just simplify this and format as `('1', '2', '3')` instead.

The issue this is working around is that MySQL would (I think?) sometimes appear to do something goofy and miss the key if you formatted…