When working from an existing plan, we weren't setting the PathOut field
for a LocalState. This required adding an outPath argument to the
StateFromPlan function to avoid having to introspect the returned
state.State interface to find the appropriate field.
To test we run a plan first and provide the new plan to apply with
`-state-out` set.
If the cached state file contains a remote type field with upper case
characters, eg 'Consul', it was no longer possible to find the 'consul'
remote plugin.
James Bardin