fix: walk ast.Ellipsis values.

Fixes #2583.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5671078

src/cmd/fix/error_test.go

@@ -42,6 +42,10 @@ func g() {
 	error := 1
 	_ = error
 }
+
+func h(os.Error) {}
+
+func i(...os.Error) {}
 `,
 		Out: `package main
 
@@ -59,6 +63,10 @@ func g() {
 	error := 1
 	_ = error
 }
+
+func h(error) {}
+
+func i(...error) {}
 `,
 	},
 	{

src/cmd/fix/fix.go

@@ -113,6 +113,7 @@ func walkBeforeAfter(x interface{}, before, after func(interface{})) {
 	case *ast.BadExpr:
 	case *ast.Ident:
 	case *ast.Ellipsis:
+		walkBeforeAfter(&n.Elt, before, after)
 	case *ast.BasicLit:
 	case *ast.FuncLit:
 		walkBeforeAfter(&n.Type, before, after)