all: delete a couple of mentions of the exp and old trees

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7551043

src/cmd/api/goapi.go

@@ -138,9 +138,7 @@ func main() {
 		}
 
 		for _, pkg := range pkgs {
-			if strings.HasPrefix(pkg, "cmd/") ||
-				strings.HasPrefix(pkg, "exp/") ||
-				strings.HasPrefix(pkg, "old/") {
+			if strings.HasPrefix(pkg, "cmd/") {
 				continue
 			}
 			if fi, err := os.Stat(filepath.Join(w.root, pkg)); err != nil || !fi.IsDir() {

src/cmd/dist/build.c

@@ -313,7 +313,6 @@ static char *unreleased[] = {
 	"src/cmd/cov",
 	"src/cmd/prof",
 	"src/pkg/old",
-	"src/pkg/exp",
 };
 
 // setup sets up the tree for the initial build.

src/cmd/vet/taglit.go

@@ -108,7 +108,6 @@ var untaggedLiteralWhitelist = map[string]bool{
 	"encoding/xml.CharData":                         true,
 	"encoding/xml.Comment":                          true,
 	"encoding/xml.Directive":                        true,
-	"exp/norm.Decomposition":                        true,
 	"go/scanner.ErrorList":                          true,
 	"image/color.Palette":                           true,
 	"net.HardwareAddr":                              true,