nuke-room-from-db.sh doesn't delete the room from communities

[rubo77]

The nuke-room-from-db.sh script doesn't nuke the room from communities
if you added a room into a community on the lefthandside and then nuke that room, it is still in the list of rooms in the community

Steps to reproduce

• using postgresql use the nuke-room-from-db.sh script on the room

Version information

• Homeserver: my own homeserver
• Version: 0.28.0
• Install method: git clone/pip
• Platform:
  • Debian squeeze version 9.3
  • Hardware: Intel Core™ i7-6700 Quad-Core (Hetzner EX41S), running in a XEN vm/container (xen 4.6)
• Version of riot-web: 0.14.2

[rubo77]

At the moment the script is removed in #3888 but there is a discussion running, how to fix the script.