Wash returns wrong type ID for external plugin that uses core plugin entries

[ekinanp]

Wash lets external plugin authors take advantage of core plugin entries. Currently, only the volume::fs entry is used. These core entries have special type IDs meant to minimize conflicts. For volume::fs, this is __volume::fs__. However, external plugin#List returns the core plugin entry version of volume::fs (i.e. volume.FS); this entry's type ID is the struct class name. Hence, there's a type ID mismatch. This affects commands like find because find cannot recurse into those entries (since its recursion stops at a nil schema).

Fix is to probably wrap core plugin entries into something that implements the external plugin entry interface.

[ekinanp]

Alternative fix is to just munge schema graph to use the raw type ID. E.g. instead of storing as __volume::fs__, we store as plugin.RawTypeID(&volume.FS{}). That's what I'll do.

[MikaelSmith]

Can revert puppetlabs-toy-chest/boltwash#9 once a fix for this is released.