savecore: default to -N /dev/ksyms?

[Thor Simon <tls%coyotepoint.com@localhost>]

It seems to me that these days /dev/ksyms is more likely to be present
and working than /netbsd is to be a source of kernel symbols.

I'd like to change savecore's default source of kernel symbols, for that
reason.

-- 
Thor Lancelot Simon
Coyote Point Systems, Inc.                      <tls%coyotepoint.com@localhost>
Millerton, NY, USA