Fix compile warning and timeout message logic in io_stream.c

I should definitely amend the commit to not say "Refactor", since I am changing behavior; however, I think what we have here is correct.

If `timeout` is negative, the stream read should block indefinitely (when we call `php_stream_set_option()` earlier in the function) and we probably shouldn't ever enter this code path where `"timed_out"` is truthy in the stream metadata.

But let's say we do somehow enter this code path and `timeout` was negative. The previous code would have used `socketTimeoutMS` in the error message, despite the fact that we changed the stream timeout via `php_stream_set_option()`.

Also, the `int socketTimeoutMS` assignment from the original code below is redundant in light of the processing I added in 
db46b1318b380ed763ecb193ba72451cbca4de94 (in hindsight, I should have updated this code in the original commit -- I didn't catch it). To be consistent, we normalize any negative timeout value (i.e. block indefinitely) as -1000 to ensure that we can consider negative `timeout` and negative `socketTimeoutMS` the same and not override the stream option unnecessarily.

Would you suggest I change `(timeout && timeout != socketTimeoutMS)` to `(timeout != socketTimeoutMS)`?