name-hash.h: move declarations for name-hash.c from cache.h

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/unpack-trees.c b/unpack-trees.c
index e8c32a4..078c53f 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -7,6 +7,7 @@
 #include "environment.h"
 #include "gettext.h"
 #include "hex.h"
+#include "name-hash.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "cache-tree.h"