Fix imports and change ldap function name

einterfaces/ldap.go

@@ -11,7 +11,7 @@ type LdapInterface interface {
 	DoLogin(team *model.Team, id string, password string) (*model.User, *model.AppError)
 	GetUser(id string) (*model.User, *model.AppError)
 	CheckPassword(id string, password string) *model.AppError
-	DoSwitch(userId, ldapId, ldapPassword string) *model.AppError
+	SwitchToEmail(userId, ldapId, ldapPassword string) *model.AppError
 }
 
 var theLdapInterface LdapInterface