What 'defconfig' really does is save the current .config to a defconfig,
so it is better named 'savedefconfig' (as other projects do).
What 'olddefconfig' really does is create a .config from a defconfig,
so rename it to 'defconfig' (as other projects do, too).
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>