A little note on your usage of the Http binding. You are calling the details script, which in turn is NOT suggested by tankerkoenig for frequent price-updates.
I haven’t tried it using a rule with your special TLS setting. If a rule would be working, you could use mine. I had it with the opening - time mode included (posted a couple of month ago, I’d have to search for it). Since OH2.1 is a bit more picky on syntax there might be some hickups, but it was running.
The rule is posted here: Getting fuel prices from Tankerkoenig.de