r1498: (merge from 3.0)

Rework our random number generation system.

On systems with /dev/urandom, this avoids a change to secrets.tdb for every fork().

For other systems, we now only re-seed after a fork, and on startup.
No need to do it per-operation.  This removes the 'need_reseed'
parameter from generate_random_buffer().

This also requires that we start the secrets subsystem, as that is
where the reseed value is stored, for systems without /dev/urandom.

In order to aviod identical streams in forked children, the random
state is re-initialised after the fork(), at the same point were we do
that to the tdbs.

Andrew Bartlett

source/rpc_server/netlogon/dcerpc_netlogon.c

@@ -150,8 +150,7 @@ static NTSTATUS netr_ServerReqChallenge(struct dcesrv_call_state *dce_call, TALL
 	pipe_state->client_challenge = *r->in.credentials;
 
 	generate_random_buffer(pipe_state->server_challenge.data, 
-			       sizeof(pipe_state->server_challenge.data),
-			       False);
+			       sizeof(pipe_state->server_challenge.data));
 
 	*r->out.credentials = pipe_state->server_challenge;