r4011: get rid of rpc_secdes.h and replace it with a single sane set of

r4011: get rid of rpc_secdes.h and replace it with a single sane set of
definitions for security access masks, in security.idl

The previous definitions were inconsistently named, and contained many
duplicate and misleading entries. I kept finding myself tripping up
while using them.
(This used to be commit 01c0fa722f80ceeb3f81f01987de95f365a2ed3d)