The log variable `%HP` includes the host for HTTP/2 but not for HTTP/1.1 (backward incompatible change?)

[Ciprian Dorin Craciun]

I've upgraded from HAProxy 1.8 to 2.1 branch, and without changing the
configuration I've observed the following inconsistency:

The `%HP` log variable used to contain only the path for both HTTP/2
and HTTP/1.1 in HAProxy 1.8.

How with HAProxy 2.1.4 (as available on OpenSUSE 15.1) the `%HP` log
variable contains the full URI (without query) for HTTP/2, however for
HTTP/1.1 it contains only the path.

Is this an expected change, or is it a backward incompatible change?

Thanks,
Ciprian.