Fix build on i386 system

Matthias Fechnerrequested to merge
mfechner/gitaly:bugfix/build_i386 into master

This fixes #6989

Rusage on i386 system is an int32 value:
https://cs.opensource.google/go/go/+/refs/tags/go1.25.4:src/syscall/ztypes_freebsd_386.go;l=31

Edited by Matthias Fechner

Merge request reports