Failed jobs will now be automatically retired. This is controlled by two
new settings:
retry_on_status - a list of statuses which will be consided failures and
result in a retry
max_retries - number of retries before giving up
Some options in config_example.py are not reachable. It makes users
confused. So make the options in the file as gobal_alias.
Signed-off-by: zhizhou.zhang <zhizhou.zhang@spreadtrum.com>