*: fix various data races detected by race detector

etcdserver/auth/auth.go

@@ -22,6 +22,7 @@ import (
 	"reflect"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
@@ -93,7 +94,9 @@ type store struct {
 	server      doer
 	timeout     time.Duration
 	ensuredOnce bool
-	enabled     *bool
+
+	mu      sync.Mutex // protect enabled
+	enabled *bool
 }
 
 type User struct {
@@ -377,6 +380,9 @@ func (s *store) UpdateRole(role Role) (Role, error) {
 }
 
 func (s *store) AuthEnabled() bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	return s.detectAuth()
 }
 
@@ -384,6 +390,10 @@ func (s *store) EnableAuth() error {
 	if s.AuthEnabled() {
 		return authErr(http.StatusConflict, "already enabled")
 	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	_, err := s.GetUser("root")
 	if err != nil {
 		return authErr(http.StatusConflict, "No root user available, please create one")
@@ -412,6 +422,10 @@ func (s *store) DisableAuth() error {
 	if !s.AuthEnabled() {
 		return authErr(http.StatusConflict, "already disabled")
 	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	err := s.disableAuth()
 	if err == nil {
 		b := false