CMWallpapers: correct package name

Very minor: "com.cyanogenmod.CMWallpapers" -> "com.cyanogenmod.wallpapers"
Make it consistent with "com.cyanogenmod.account" and "com.cyanogenmod.filemanager"

Change-Id: If1b46343b603d2cb991874828b336e8ac8c6d90e
Merge "CMWallpapers: correct package name" into cm-11.0