s3-rpc_server: Fix handling of fragmented rpc requests.

s3-rpc_server: Fix handling of fragmented rpc requests.

We need to call pipe_init_outgoing_data() as the first thing in
process_complete_pdu(). Otherwise the caller may use uninitialized
memory and tries to write a response into the socket.

The problem happens only if a real socket is used, which means
in all cases for master and only with external rpc daemons in v4-0
and v4-1.

The problem looks like this in the logs.

    [2014/03/20 14:49:35.531663, 10, pid=7309, effective(0, 0), real(0, 0), class=rpc_srv] ../source3/rpc_server/srv_pipe.c:1627(process_complete_pdu)
      Processing packet type 0
    [2014/03/20 14:49:35.531695, 10, pid=7309, effective(0, 0), real(0, 0), class=rpc_srv] ../source3/rpc_server/srv_pipe.c:1472(dcesrv_auth_request)
      Checking request auth.
    [2014/03/20 14:49:35.531738, 10, pid=7309, effective(0, 0), real(0, 0)] ../source3/rpc_server/rpc_server.c:521(named_pipe_packet_process)
      Sending 1 fragments in a total of 0 bytes
    [2014/03/20 14:49:35.531769, 10, pid=7309, effective(0, 0), real(0, 0)] ../source3/rpc_server/rpc_server.c:526(named_pipe_packet_process)
      Sending PDU number: 0, PDU Length: 4294967228
    [2014/03/20 14:49:35.531801,  2, pid=7309, effective(0, 0), real(0, 0)] ../source3/rpc_server/rpc_server.c:565(named_pipe_packet_done)
      Writev failed!
    [2014/03/20 14:49:35.531845,  2, pid=7309, effective(0, 0), real(0, 0)] ../source3/rpc_server/rpc_server.c:595(named_pipe_packet_done)
      Fatal error(Message too long). Terminating client(127.0.0.1) connection!

BUG: https://bugzilla.samba.org/show_bug.cgi?id=10481

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Guenther Deschner <gd@samba.org
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Thu Mar 20 18:30:17 CET 2014 on sn-devel-104

(cherry picked from commit 5277fc4d0393ffe2e415ad26610b36d2986c62d7)