Prototyping for the volser directory

Prototyping for the volser directory

Prototyping and warning message reduction for the volser directory.
Adds physio.h and dumpstuff.h as internal header files,
Many error code variables are changed from being afs_int32, to the
'Error' typedef, to remove signed comparison errors.

Reviewed-on: http://gerrit.openafs.org/19
Reviewed-by: Russ Allbery <rra@stanford.edu>
Verified-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>