Find the real folder (and message info UID) for the given vinfo.
When the realuid is not null and it's set, then use g_free to
free it, when no longer needed.
| this | |
| vinfo |
a VeeMessageInfo to search for |
| realuid |
if not null, set to the UID of the real message info |
|
a real (not virtual) Folder, which the |