Reported PM data is stored in reports table but not used

When a private message is reported, we store the message in its current state in the reports table. When displaying it in the report, however, the version displayed is the current one from the private messages table. There is a (rather unlikely) possibility that the author may report his PM, and then edit it afterwards. In which case, the context in the report may no longer make sense to the moderator if the version that he sees is the current one instead of the reported state. We should possibly make use of the data that we store in the reports table and display both the current and reported stated as is done with post reports... or just avoid wasting space by not storing the PM in the reports table.