Fix dotrun clean-cache command

[lyubomir-popov]

Currently, the only way to get rid of old cache is to uninstall and reinstall the snap. I had two folders, 32 and 33, which I assume are some sort of versions, full of 1GB of (mostly repeating) caches.

[jkfran]

I am closing this issue as it doesn't affect dotrun v2. Thank you!

[nottrobin]

Are you sure? We've now introduced a cache volume - that could get big. Maybe worth having an option to clear it out.

[jkfran]

We already had dotrun clean-cache but I just found out this one is not working, presumably because it should remove the items in the folder, not the folder itself:

dotrun clean-cache
Checking for dotrun image updates...

[ $ rm -rf /home/ubuntu/.cache ]

rm: cannot remove '/home/ubuntu/.cache': Device or resource busy

= `rm -rf /home/ubuntu/.cache` errored =

Okay, I will reopen this issue, but I will change the issue title.