Don't hide the bouncer when resetting keyguard if keyguard is already

showing.

This avoids hiding the bouncer if the user could already be interacting
with it.

Fixes: 277614049
Test: set lock timeout to 5s, pressed power button to start dreaming and
lock device, quickly pulled up the bouncer, and verified it doesn't
dismiss itself after 5s

Change-Id: I59b3867c05e2698737e52eb355749c8b0e734925