distro-import doesn't create a slim_cluster
The distro constructor, in its normal state, assumes that group packages defining installation images exist. An OI import doesn't create a slim_cluster, or a 'redistributable' (nor AI or text, if they exist yet).
The cluster used for OI import should define slim_cluster and redistributable correctly (similarly to how it's done in the 'real' cluster files).
This is necessary for any kind of sane use of the distro constructor (the slim_install used for oi_147 was manually adjusted from 134).