pack: move {,re}prepare_packed_git and approximate_object_count

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/server-info.c b/server-info.c
index 5ec5b1d..26a6c20 100644
--- a/server-info.c
+++ b/server-info.c
@@ -3,6 +3,7 @@
 #include "object.h"
 #include "commit.h"
 #include "tag.h"
+#include "packfile.h"
 
 /*
  * Create the file "path" by writing to a temporary file and renaming