Needless change in affinity function

[fulmicoton]

Rust changed the endianness of the IP address internal representation.

This has an impact on its "hash", which in turn has an impact on our affinity function.

rust-lang/rust@fce1dec

As spotted and fixed by @trinity-1686a in #5564

The change is impactful for companies running quickwit with a large cache and wanting to upgrade.
We need to make sure our affinity function in 0.9 is the same as in 0.8.

[fulmicoton]

Actually I don't understand how rust-lang/rust@fce1dec would make a difference on most little endian (pretty much everything) arch. I assume the problem is coming from a different commit.

[trinity-1686a]

there are two related commits:

• rust-lang/rust@ba62034 changed how hash of ip are computed (from array/slice of u8 to a single u32)
• rust-lang/rust@fce1dec made the hash slightly faster on big endian at the cost of being platform dependent (we only support little endian, so it has little impact on us)