If the build does not exist we can get an error when starting up:
INTERNALERROR> Exception: .config does not exist; try passing --build
option?
Exception ignored in atexit callback: <function cleanup at ...>
Traceback (most recent call last):
File "test/py/conftest.py", line 697, in cleanup
show_timings()
File "test/py/conftest.py", line 644, in show_timings
if ubconfig and ubconfig.timing:
^^^^^^^^^^^^^^^
Fix this by setting up the timing member at the start.
Signed-off-by: Simon Glass <simon.glass@canonical.com>