lava_wait_jobs.py: Print exception traceback in case of retries

Current retries on the level of main() are very crude and often don't
help, as when restarting from the very beginning there's a high chance
that another issue (e.g. a timeout) occurs. To help to investigate
how to perform retries in a better manner, add this additional logging.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I8ce77e5e52b07667a7096aaf98fd5d1eceb4e596
1 file changed