Well, in fact it works (make oldconfig throws only a warning when it sees
both SH_IS_HUSH=y and SH_IS_NONE=y), but let's be nice.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The same can be done for msh, but we are probably better off just deleting it
in a next versio or two.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>