Don't work on anki 2.1.20

[ilovlowphy]

Don't work on anki 2.1.20. When I go back 2.1.15, it gets back normal.

[bosconb]

2.1.20 in mac, everything is ok for me so far

[Junyu25]

Yeah, I got error like this when I update to Anki 2.1.20
@tsudoko I don't know whether if it's because I have a large deck, or it's incompatible with Anki2.1.20.

[mrozigor]

I was able to run Anki 2.1.20 and sync it with anki-sync-server, but probably only data (no media). It looks like it tries to sync media with ankiweb, regardless of what is set in SYNC_BASE variable. When I put my server IP in method that creates media sync URL (in Anki), then anki-sync-server rejects request (403; it looks like the session isn't initialized earlier).

[Junyu25]

@mrozigor You are right, I can sync the card data, but when it comes to media, it failed.
So I Check Media file and find out there are some media use it card but not in my media folder.
After I delete the card field that contain the missing media, it sync successfully.
Note that I reinstall the anki-sync-server and also install the pyaudio to check if is required for anki 2.1.20.

[mrozigor]

I hope that my PR will help with some of the issues.