Fix operator precedence;

[bjornbytes]

Bitwise AND has lower precedence than equality.

[slime73]

This actually breaks things for me, e.g. this code hits the assert now when using the schannel backend:

local code, body = https.request("https://example.com")
assert(code == 200, body)

So there might be a lot more to unravel with the changed code in order to properly address it. However since the new WinINet backend is used by default now instead of the SChannel backend, maybe it doesn't matter.

[slime73]

I think I'll revert the change for now since I'd rather all backends to work than not, and we can decide what to do from there.

[bjornbytes]

Oops, I was testing on the wrong backend. Looks like the SChannel backend always looks at the flags regardless of whether QueryContextAttributes was successful, but because it gets the operator precedence wrong it ends up accidentally doing nothing. At this point I guess I'll just back away slowly and disable that backend.

[MikuAuahDark]

With recent commits, WinINet is used instead of Schannel unless user sets certain environment variables to disable WinINet.