Update categorization for SRR files of the category Unknown when something changes

[Gfy]

One user has uploaded more than 1k SRR files for MP3 releases, created with ReScene .NET 1.3.3 GUI (beta) software. No SRS files are created. This caused the SRR to be categorized as Unknown. Later, SRS files are added by other uploaders. An example:

http://www.srrdb.com/release/details/Arno-Future_Vintage-FR-2012-SNOOK

When adding .srs files to an SRR of the category Unknown, the category must be rechecked automatically.

[Gfy]

The batch script RefreshUnknownCategory can fix these issues on older releases.