Minor OatFile ownership and --oat-fd= argument formatting

Change-Id: Idd2e6aca574b473222d75a0fab1fe7538c6a787b
diff --git a/src/oatdump.cc b/src/oatdump.cc
index a664852..dd46896 100644
--- a/src/oatdump.cc
+++ b/src/oatdump.cc
@@ -274,6 +274,7 @@
     os << "\n";
     os << std::flush;
 
+    class_linker->RegisterOatFile(*oat_file);
     OatDump::Dump(oat_location, host_prefix, os, *oat_file);
   }