Launching spot instances creates persistent spot requests

[dzubo]

Sequence:

1. fe2 launch spot1 base 80 m5.2xlarge --spot
2. Wait until instance provided.
3. fe2 terminate spot1
4. Check EC2 web console minute later - there is a new spot instance spinned, same type as was requested for spot1, but without a name.
5. Check 'Spot Requests' section in web console: we see active (green dot) spot request with a type 'Persistent'. So AWS recreates terminated spot instances, but outside of the scope of fe2.

That can lead to unwanted spending easily.