rfc822 is also known as .EML file format, you can see all info about importing into Thunderbird HERE.
Interesting text from the link:
If you have problems importing .EML files using the ImportExportTools extension try using eml2mbx to convert the .EML files to a mbox file and then import the mbox file using the ImportExportTools extension. A Google search will find several eml to mbox conversion programs. Whats unusual about this one is that provides a lot of control over how it converts the .EML files using a "eml2mbx.ini" file.
In short you must convert EML to mbox format.
There is also info for KMail and links HERE.
Also you can use eml2mbox ruby script to convert your emails to mbox, which can be imported into Evolution. I was able to convert the sample you provided and import it. The script with all info needed can be found HERE.