REORG: use the name sock_raw instead of stream_sock

We'll soon have an SSL socket layer, and in order to ease the difference
between the two, we use the name "sock_raw" to designate the one which
directly talks to the sockets without any conversion.
diff --git a/src/session.c b/src/session.c
index feb0283..3024599 100644
--- a/src/session.c
+++ b/src/session.c
@@ -40,9 +40,9 @@
 #include <proto/queue.h>
 #include <proto/server.h>
 #include <proto/sample.h>
+#include <proto/sock_raw.h>
 #include <proto/stick_table.h>
 #include <proto/stream_interface.h>
-#include <proto/stream_sock.h>
 #include <proto/task.h>
 
 struct pool_head *pool2_session;