Proposal to drop libgsf from external deps

[Frederic Peters <fpeters gnome org>]

Hello,

libgsf was used by librsvg to decompress svgz files, but this is now
done using GZlibDecompressor, and to build an optional miner for
Microsoft documents in Tracker.

This is not a big module at all but this is a small step in reducing
our set of external dependencies.

Are you fine with this?


        Frederic