overview-manual, mega-manual: Updated SDK generation image

The image needed a little bit of clean up.

(From yocto-docs rev: d4fb680be194b7f9b192e06f0081a09504649633)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>