Wallpaper Improvements CLs (2 of 3): New Overlay Wallpaper

Updated default overlay wallpaper file to be PNG file with 1 pixel of
Hex RGB: #212121.
"#212121" is the value currently used by LandscapeWallpaperService,
which is being removed in favor of this static image solution.

b/37993879

Test: Manually

Change-Id: I11d782aa6f3e294b84293c0a5191e28e24b2904c
diff --git a/overlay/frameworks/base/core/res/res/drawable-nodpi/default_wallpaper.png b/overlay/frameworks/base/core/res/res/drawable-nodpi/default_wallpaper.png
index 8ed1509..f830df0 100644
--- a/overlay/frameworks/base/core/res/res/drawable-nodpi/default_wallpaper.png
+++ b/overlay/frameworks/base/core/res/res/drawable-nodpi/default_wallpaper.png
Binary files differ