I am using a Nexus 7 with the Android 5.0 preview build.
On this page http://developer.android.com/tools/support-library/index.html
I see
You seem to have a working drawer as I read it, if not, the Documentation on "Creating a Navigation Drawer" is pretty good.
Updated ActionBarDrawerToggle, which contains the menu-to-arrow animation

The above quote refers to Create a new ActionBarDrawerToggle with arrow and hamburger menu commit.
As a related one: setDrawerIndicatorEnabled was added in Add ability to disable drawer indicator in new ArrowDrawer.
So make sure setDrawerIndicatorEnabled is not called with false and use
import android.support.v7.app.ActionBarDrawerToggle;
instead of
import android.support.v4.app.ActionBarDrawerToggle;
which should be pretty obvious from deprecation warnings anyway:
@deprecated Please use ActionBarDrawerToggle in support-v7-appcompat.
Probably also need
// - showHome|homeAsUp
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);