Yet more #include de-duplication.

ok deraadt@ tedu@
remove the inspect debug command. should not be used by users, who are not
supposed to know what fingerprints are or that they exist.
rename fingerprint struct field. no longer exposed to users, but since it's
not technically a fingerprint as others understand the term, pick another.
now it's a keynum!
after an email from Florian Weimer
useless change. overwriting the nul byte with a newline means b64_ntop
can use the whole buffer, even the last byte.