Rename printf cast helpers and clean up format string warnings

Rename printf cast helpers and clean up format string warnings

Some confusion had ensued about the usage of our printf cast helper
functions. Rename these to attempt to allay that confusion, and restore
the functions themselves to their original definitions.

Essentially, afs_printable_int32_ld() and friends are helpers to go
from afs specifc types to things that can be emitted by printf without
causing compiler warnings.

Also clean up some additional warnings from type mismatches between
escapes in printf format strings and the variables being printed.

Reviewed-on: http://gerrit.openafs.org/50
Verified-by: Russ Allbery <rra@stanford.edu>
Reviewed-by: Russ Allbery <rra@stanford.edu>