Use None for optional keyword arguments

[ddebeau]

Convention is to use None for optional arguments and set the default values in code.

zfs_uploader/zfs_uploader/job.py

Lines 74 to 76 in ccfa4b6

	def __init__(self, bucket, access_key, secret_key, filesystem,
	region='us-east-1', cron=None, max_snapshots=None,
	max_incremental_backups=None, storage_class='STANDARD'):