Tighten up fill_authenticator

Change-Id: Iaac0ae569f6111b32c053b6d5bbe8ae1ed75ac93
Tighten up GetResponse

Change-Id: I248d75df9255df4afe2ede976c142a58b186a244
Bring sanity to UUID handling

Do not insist on a UUID being present for the authenticator (or
go to great lengths to construct one), as this is only specified
to be present when the cache manager (or similar) is acting as the
RX client.  Instead, let the client specify a UUID parameter when
constructing a security object, optionally NULL, and store it in
the client's privateData.  Use this field in the authenticator
if it is present.

Change-Id: Ic10edf876127a9f4dfcb5f5e1ca8680bfe96fd99
rxgk_key_number to do key derivation more properly

Change-Id: Ieea585ff8ee668808f3bd39d4127b71ca1ad9e1f
rxgk_update_kvno to put a new kvno in the connection state

The local (32-bit) value is in a different place for clients and
servers, sigh.

Change-Id: Iff3a27332b279bf092b2792d5465a649cb2ad5b1
Use key numbers properly for derived keys

Get the right number from local+wire knowledge and use it when deriving
the key.

Change-Id: Ib25b0515dc5a92a8966f543ec27873fd0d6661d9
Tighten up decrypt_authenticator error handling

We can't jump to cleanup with the XDRs uninitialized.

Change-Id: I7c7cb947bb22d941eb791e9c44736990ca4907d9
Fix kvno type (should be unsigned)

Change-Id: Ie271292bd24968ddf5dcf8edec409e2ecc7711bc
Flesh out GetStats

Still have no statistics to report, as we don't save them
in the packet-processing routines.

Change-Id: If7ec2858aced87e6a7c300c1d277700ee8927fad
track packet/byte stats in Check/PreparePacket

Change-Id: I04536c59f244464ff4c198105e3b08f19a10325c