Fix duplicate Reboot dialog open

If hold down the power button it shows the reboot dialog
If hold down again the power button open new reboot dialog but the old dialog still open instead of close

Patchset 1: Initial commit
Patchset 2: Rebase
Patchset 3: Remove dependencies
Patchset 4: [Rashed] Rebase

Change-Id: Ia55b279c45778a78cf6b8c7eb03cfc62e7e3393d