cerbero: Use a list for the download command, not a string
cerbero: Use a list for the download command, not a string

We split the string immediately in async_call, so no point doing this.
Just pass a list from the start, which also avoids shell quoting
issues.

nirbheek/cerbero,nirbheek/cerbero,GStreamer/cerbero,GStreamer/cerbero,nirbheek/cerbero,nirbheek/cerbero,GStreamer/cerbero,GStreamer/cerbero,GStreamer/cerbero