Remove unread private transport members

internal/engine/import_spec.go

@@ -35,7 +35,6 @@ type importDeclarationSpec struct {
 	pattern       []string
 	patternSet    bool
 	exclude       []string
-	excludeSet    bool
 	depth         int
 	depthSet      bool
 	destination   Path
@@ -327,7 +326,7 @@ func parseImportWildcardAssignment(spec *importDeclarationSpec, field string, no
 	case "pattern":
 		spec.pattern, spec.patternSet = values, true
 	case "exclude":
-		spec.exclude, spec.excludeSet = values, true
+		spec.exclude = values
 	}
 	return nil
 }