Change how File/Directory/Link .delete works.

runtime/bin/file.h

Index: runtime/bin/file.h
diff --git a/runtime/bin/file.h b/runtime/bin/file.h
index 0895a8466d37fad19e955e56e8b651e2e1c13727..cc80b2f40575499fc6b9a6e04c99a332a9425b0b 100644
--- a/runtime/bin/file.h
+++ b/runtime/bin/file.h
@@ -131,6 +131,7 @@ class File {
   static bool Create(const char* path);
   static bool CreateLink(const char* path, const char* target);
   static bool Delete(const char* path);
+  static bool DeleteLink(const char* path);
   static off_t LengthFromPath(const char* path);
   static time_t LastModified(const char* path);
   static char* LinkTarget(const char* pathname);