No error message when hash is not specified

Bug reproduces when running `replicate prepare/start/stop` command without specifying either blue or green hash: **deepify replicate [prepare/start/stop] --blue --green --resources resource_name**

`Cannot read property 'split' of null` error appears. Please display error message that blue/green hash(or both) is required.

Note: bug also reproduces when `--resources` value is not specified.