keyguard: Do not trigger a wake up when hiding lockscreen

* This piece of code was introduced in commit:
      Swipe up to unlock when pulsing
      Change-Id: Ida5adb6a18f3ee992b1d154e10b35ba244f5b712
  However, it appears to not be needed and instead causes the device
  to wakeup right after dozing with no lockscreen set.

* Remove it and test with:
  adb shell am broadcast -a com.android.systemui.doze.pulse com.android.systemui
  The device can still be unlocked from pulsing state.

Change-Id: Ib5c2f930bd4de04cbf8f89f12d046f30c9b32a52