CLEANUP: proto_tcp: Remove useless header inclusions.

I guess "sys/un.h" and "sys/stat.h" were included for debugging purposes when
"proto_tcp.c" was initially created. There are no more useful.
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 64ffb83..4ca6fc2 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -25,9 +25,7 @@
 
 #include <sys/param.h>
 #include <sys/socket.h>
-#include <sys/stat.h>
 #include <sys/types.h>
-#include <sys/un.h>
 
 #include <netinet/tcp.h>
 #include <netinet/in.h>