Hangs after a few actions

[JosiahWI]

Minetest version

b11d2d83939ee67ac66cfb70797841d2fee42e0c (headless-renderer)

Summary

test_loop.py prints out the following and hangs:

Waiting for obs...
Received obs: (0, 0, 3)
Sending action: OrderedDict([('backward', 1), ('dig', 1), ('drop', 1), ('esc', 0), ('forward', 0), ('hotbar_next', 0), ('hotbar_previous', 1), ('inventory', 0), ('jump', 0), ('left', 0), ('middle', 0), ('mouse', array([-882, -607])), ('place', 1), ('right', 0), ('slot1', 0), ('slot2', 0), ('slot3', 0), ('slot4', 0), ('slot5', 1), ('slot6', 1), ('slot7', 1), ('slot8', 0), ('sneak', 0)])
Waiting for obs...
Received obs: (600, 1024, 3)
Sending action: OrderedDict([('backward', 0), ('dig', 1), ('drop', 0), ('esc', 1), ('forward', 0), ('hotbar_next', 0), ('hotbar_previous', 1), ('inventory', 1), ('jump', 0), ('left', 0), ('middle', 0), ('mouse', array([573, 234])), ('place', 0), ('right', 1), ('slot1', 0), ('slot2', 0), ('slot3', 1), ('slot4', 1), ('slot5', 0), ('slot6', 0), ('slot7', 1), ('slot8', 0), ('sneak', 0)])
Waiting for obs...

It's caused by the aforementioned commit, which introduced the deletion of a buffer that was not being deleted due to a syntax error. Maybe we aren't supposed to delete buffer at all. I haven't looked into it much yet.

Steps to reproduce

Compile the headless renderer and run hacking_testing/test_loop.py.