Fix compile error

server/ldap.go

@@ -205,8 +205,11 @@ func newLDAPBackend(config *Config) (*ldapBackend, error) {
 	}
 
 	// Read the bind password.
-	bindPw := config.LDAPConfig.BindPw
-	if bindPw == "" {
+	var bindPw []byte
+	if config.LDAPConfig.BindPw != "" {
+		bindPw = []byte(config.LDAPConfig.BindPw)
+	} else {
+		var err error
 		bindPw, err = ioutil.ReadFile(config.LDAPConfig.BindPwFile)
 		if err != nil {
 			return nil, err