DeskClock: Fix background notification color of the stopwatch

Remove colors and update the targetsdk so that it uses the proper
colors as defined for L

Change-Id: I2717995c0efa2cd8ac1e43bb3bbc6278b9fbfc8a
Merge branch 'cm-12.0' of git://github.com/CyanogenMod/android_packages_apps_DeskClock into cm-12.0