CherryPick 35530d from master to mr0. do not merge.

qemu.hw.mainkeys indicates if the device has h/w main (home/back) keys.

If it has main keys, then the navigation bar is *not* displayed.

Change-Id: Idb36a1f787360363a009463f0c016a423594a5b9

Author: Xavier Ducrohet

policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

@@ -827,8 +827,8 @@ public void setInitialDisplaySize(int width, int height) {
         // See also hasNavigationBar().
         String navBarOverride = SystemProperties.get("qemu.hw.mainkeys");
         if (! "".equals(navBarOverride)) {
-            if      (navBarOverride.equals("1")) mHasNavigationBar = true;
-            else if (navBarOverride.equals("0")) mHasNavigationBar = false;
+            if      (navBarOverride.equals("1")) mHasNavigationBar = false;
+            else if (navBarOverride.equals("0")) mHasNavigationBar = true;
         }
 
         mNavigationBarHeight = mHasNavigationBar