Some simple fixes to improve python 3 compatability in scons. Change-Id: I89aba6ed9d73ee733307c57e033c636029d9cb7a Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23264 Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Maintainer: Jason Lowe-Power <jason@lowepower.com> Tested-by: kokoro <noreply+kokoro@google.com>