MINOR: h1: properly pre-initialize err_pos to -2

This way we maintain the old mechanism stating that -2 means we block
on errors, -1 means we only capture them, and a positive value indicates
the position of the first error.
diff --git a/include/proto/h1.h b/include/proto/h1.h
index b6c6135..c82e17a 100644
--- a/include/proto/h1.h
+++ b/include/proto/h1.h
@@ -309,7 +309,7 @@
 	h1m->flags = H1_MF_NONE;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
-	h1m->err_pos = 0;
+	h1m->err_pos = -2;
 	h1m->err_state = 0;
 	return h1m;
 }
@@ -323,7 +323,7 @@
 	h1m->flags = H1_MF_RESP;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
-	h1m->err_pos = 0;
+	h1m->err_pos = -2;
 	h1m->err_state = 0;
 	return h1m;
 }