pack: move find_sha1_pack()

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/http-walker.c b/http-walker.c
index ee049cb..1ae8363 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -4,6 +4,7 @@
 #include "http.h"
 #include "list.h"
 #include "transport.h"
+#include "packfile.h"
 
 struct alt_base {
 	char *base;