WindowlessGlxContext: no supported framebuffer configuration found; WindowlessContext: Unable to create windowless  context 

When I try to creat the simulator following `dataset/generate_dataset.py` using 
```
cfg = make_cfg(sim_setting)
sim = habitat_sim.Simulator(cfg)
```
I got 
```
Platform: :WindowlessGlxContext: no supported framebuffer configuration found
WindowlessContext: Unable to create windowless  context 
```
Has anyone else had this problem?
