Update CHANGELOG.md

CHANGELOG.md

@@ -27,6 +27,7 @@ IMPROVEMENTS:
   * builder/qemu: User variable expansion in `ssh_key_path` [GH-918]
   * builder/virtualbox: Support an `export_opts` option which allows
       specifying arbitrary arguments when exporting the VM. [GH-945]
+  * builder/virtualbox: Run vboxmanage commands just before exporting [GH-664]
   * builder/vmware: Workstation 10 support for Linux. [GH-900]
   * builder/vmware: add cloning support on Windows [GH-824]
   * command/build: Added '-parallel' flag so you can disable parallelization