func RunGoWalkInstall(cfg *conf.GobazelConf, workspace, proj string) {
	filepath.Walk(filepath.Join(workspace, proj), func(path string, info os.FileInfo, err error) error {
		if info.Name() == "BUILD" {
			if dir, err := filepath.Rel(workspace, path); err == nil {
				dir = filepath.Dir(dir)
				for _, v := range cfg.Vendors {
					if strings.HasPrefix(dir, v) {
						return nil
					}
				}
				RunGoInstall(cfg, filepath.Join(cfg.GoPkgPrefix, dir))
			}
		}
		return nil
	})
}
RunGoWalkInstall walks the given proj directory and run "go install"
for each go package.
package exec
import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"github.com/linuxerwang/gobazel/conf"
)
func RunGoInstall(cfg *conf.GobazelConf, goPkg string) {
	cmd := fmt.Sprintf("go install %s", goPkg)
	fmt.Print(cmd)
	if err := RunCommand(cfg, cmd); err != nil {
		fmt.Println(" (failed!)")
	} else {
		fmt.Println(" (done)")
	}
}