xfs_logprint: Add log item printing for ATTRI and ATTRD

xfs_logprint: Add log item printing for ATTRI and ATTRD

This patch implements a new set of log printing functions to print the
ATTRI and ATTRD items and vectors in the log.  These will be used during
log dump and log recover operations.

Though most attributes are strings, the attribute operations accept
any binary payload, so we should not assume them printable.  This was
done intentionally in preparation for parent pointers.  Until parent
pointers get here, attributes have no discernible format.  So the print
routines are just a simple print or hex dump for now.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>