remove unused field and extra assignment

internal/terraform/context_import.go

@@ -62,7 +62,6 @@ func (c *Context) Import(config *configs.Config, prevRunState *states.State, opt
 		State:              state,
 		RootVariableValues: variables,
 		Plugins:            c.plugins,
-		skipRefresh:        true,
 		Operation:          walkImport,
 	}
 

internal/terraform/graph_builder_plan.go

@@ -54,10 +54,6 @@ type PlanGraphBuilder struct {
 	// where we _only_ do the refresh step.)
 	skipPlanChanges bool
 
-	// CustomConcrete can be set to customize the node types created
-	// for various parts of the plan. This is useful in order to customize
-	// the plan behavior.
-	CustomConcrete                  bool
 	ConcreteProvider                ConcreteProviderNodeFunc
 	ConcreteResource                ConcreteResourceNodeFunc
 	ConcreteResourceInstance        ConcreteResourceInstanceNodeFunc