'make check-acceptance' odd error: "'bytes' object has no attribute 'encode'"

[Peter Maydell]

I just got this running 'make check-acceptance': does it
ring a bell with anybody?

[etc]
Fetching asset from
tests/acceptance/replay_kernel.py:ReplayKernelSlow.test_mips64el_malta_5KEc_cpio
Fetching asset from
tests/acceptance/replay_kernel.py:ReplayKernelSlow.test_mips64el_malta_5KEc_cpio
Fetching asset from
tests/acceptance/replay_kernel.py:ReplayKernelSlow.test_mips_malta32el_nanomips_4k
Fetching asset from
tests/acceptance/replay_kernel.py:ReplayKernelSlow.test_mips_malta32el_nanomips_16k_up
Fetching asset from
tests/acceptance/replay_kernel.py:ReplayKernelSlow.test_mips_malta32el_nanomips_64k_dbg
Fetching asset from
tests/acceptance/reverse_debugging.py:ReverseDebugging_AArch64.test_aarch64_virt
Fetching asset from
tests/acceptance/virtio-gpu.py:VirtioGPUx86.test_virtio_vga_virgl
Error running method "pre_tests" of plugin "fetchasset": 'bytes'
object has no attribute 'encode'
JOB ID     : 71b2d5569d9ccc8b68957d3ad2b2026bea437d66
JOB LOG    : 
/home/petmay01/linaro/qemu-from-laptop/qemu/build/clang/tests/results/job-2021-03-23T15.09-71b2d55/job.log
 (001/142) tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_tcg:
PASS (465.84 s)
 (002/142) tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_kvm:
PASS (27.46 s)
 (003/142) tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_q35_tcg:
PASS (99.43 s)
[etc]

thanks
-- PMM