no min_stat defined in Simple#set_keytab but still referenced

[zenchild]

@zenchild in this method there is no min_stat defined in here right? Any explanation that why you use undefined min_stat in here?

Originally posted by @Zogoo in #29 (comment)

[zenchild]

I looked at the MIT source and they are just passing a literal 0 for min_stat. I will mirror the gssapi gem to do the same.