commit.h: reduce unnecessary includes

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/http-push.c b/http-push.c
index 637a4e9..3f18498 100644
--- a/http-push.c
+++ b/http-push.c
@@ -15,6 +15,7 @@
 #include "setup.h"
 #include "sigchain.h"
 #include "strvec.h"
+#include "tree.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "commit-reach.h"