creation of a multipolygon without outer

[Mahabarata]

Hi,

see #31

The result =
we have a relation with only one member with the role inner : no way with the role outer means this relation is dead, it is a bad data in the osm database.

Best regards

[systemed]

See #31 - Potlatch 3 does not have a validator, so "I was able to intentionally model wrong data and then upload it without a warning" is not a bug.