Invalid creatorid is always EINVAL, not only when we are in verbose mode.
Fix DIOCADDSTATE operation.
To reduce the amount of arithmetic performed in the various radix tree
functions, reverse the numbering scheme for the levels.  The highest
numbered level in the tree now appears near the root instead of the leaves.

Sponsored by:	EMC / Isilon Storage Division
Better debug message.
Return meaningful error code from pf_state_key_attach() and
pf_state_insert().