CLEANUP/CONTRIB: hpack: remove some h1 build warnings

These are inherited by recent reorganization to the H1 code.
diff --git a/contrib/hpack/decode.c b/contrib/hpack/decode.c
index 006c909..9ef80f0 100644
--- a/contrib/hpack/decode.c
+++ b/contrib/hpack/decode.c
@@ -18,7 +18,6 @@
 #include <common/chunk.h>
 #include <common/hpack-dec.h>
 #include <common/mini-clist.h>
-#include <proto/h1.h>
 
 #define MAX_RQ_SIZE 65536
 #define MAX_HDR_NUM 1000