Fix NPE for `unexceptional-status-for-request?` (#474)
Fix NPE for `unexceptional-status-for-request?` (#474)

Fixes `(unexceptional-status-for-request? {:unexceptional-status nil}
200) => NPE`. I.e. if you have no `:unexceptional-status` key, this
will work fine, but if this key is present then `nil` will be used as fn
dakrone/clj-http