* cmd/stindex: Unify access to key from cached variable.
Avoid calling the Key() method from the iterator each time the value
is needed. Just reuse the cache variable already assigned before the
switch block.
* cmd/stindex: Display the prefix byte value for unknown key types.
Make it easier to diagnose corrupt / unknown key type entries by
showing their decimal value, correlating with the definitions in
keyer.go.
* cmd/stindex: Add missing KeyType values in stindex dump code.
Recently added DB key prefixes KeyTypeBlockListMap and KeyTypeVersion
were unknown to the stindex dumping tool. Add basic parsing to dump
their key structure.
André Colomb