Need Ctrl+C for 3 times to stop program

[junaruga]

When users want to stop the rpmlb by Ctrl+C, Need to enter Ctrl+C to stop it.
The reason is maybe for the retrying logic with max: 3.
Maybe the program is handling the SIGINT internally, and retrying right now.

Change stopping the program with 1 time Ctrl+C.

rpmlb/builder/base.py

    @retrying.retry(stop_max_attempt_number=3)
    def build_with_retrying(self, package_dict, **kwargs):
        self.build(package_dict, **kwargs)