Do not allow lights out mode for old apps.

Legacy applications using FLAG_FULLSCREEN do so principally
to get as much screen real estate as possible; reducing
clutter is usually a secondary concern. The new UI style
takes care of the latter for the most part, and the former
is irrelevant because the xlarge system bar never goes away.

Lights out---and with it the disappearance of important
systemwide navigation controls---is probably *not* something
these apps are expecting!  Consider a game: it might want
FLAG_FULLSCREEN on phone to take over your entire display,
but might also rely on menu (to pause the game or bring up
options) and home (to allow you to exit). Lights out makes
these tasks much harder on the user because those buttons
aren't visible anymore.

So, to mitigate this potentially confusing situation, we now
disable lights out for fullscreen legacy apps.

[Hack, er, cleverness alert: We use NEEDS_MENU_KEY as a
shorthand for "legacy app." This flag is set by
pre-Honeycomb apps by default, but even an app built against
the current API can request this flag; be forewarned that if
you do, you won't get lights out mode in this particular
system bar implementation when you use FLAG_FULLSCREEN.]

Change-Id: If90d8354114ba45f9485b935b87ee575a30b9f87