Revert "Remove hidden attachments in OOM"
This reverts commit 8fe7ead789806ccfbab5e690a7e747a6bf8aa393.
By removing the hidden MOSS attachment we open up
a can of possible data loss issues. Because our revert
code etc. relies on the fact that the MOSS attachment
is available.
- GnuPG-Bug-Id: T4731