CONTRIB: spoa_example: allow to compile outside HAProxy.

Don't include haproxy's includes anymore and use a local copy instead.
diff --git a/contrib/spoa_example/spoa.c b/contrib/spoa_example/spoa.c
index 351313a..ee2e3de 100644
--- a/contrib/spoa_example/spoa.c
+++ b/contrib/spoa_example/spoa.c
@@ -21,7 +21,9 @@
 #include <errno.h>
 #include <stdio.h>
 #include <signal.h>
+#include <arpa/inet.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <sys/socket.h>
 #include <err.h>
 #include <ctype.h>
@@ -33,10 +35,9 @@
 #include <event2/event_struct.h>
 #include <event2/thread.h>
 
-#include <common/mini-clist.h>
-#include <common/chunk.h>
-
-#include <proto/spoe.h>
+#include <mini-clist.h>
+#include <spoe_types.h>
+#include <spop_functions.h>
 
 #define DEFAULT_PORT       12345
 #define CONNECTION_BACKLOG 10