Ghostscript Error, Stuck in Processing

Using the latest master, we can not extract data on latest Ubuntu 64 (LTS). The Excalibur is stuck in 'Processing Step'. Using Ghostscript version (9.50~dfsg-5ubuntu4.1).

```
127.0.0.1 - - [06/Aug/2020 12:54:49] "GET /workspaces/eee2199b-6de1-4d36-8131-abc25fcca6cf HTTP/1.1" 200 -
GPL Ghostscript 9.50: Unrecoverable error, exit code 1
ERROR:root:-100
Traceback (most recent call last):
File "Code/Camelot-dev/excalibur/.venv/lib/python3.8/site-packages/excalibur_py-0.4.3-py3.8.egg/excalibur/tasks.py", line 56, in split
with Ghostscript(*gs_call, stdout=null) as gs:
File "Code/Camelot-dev/excalibur/.venv/lib/python3.8/site-packages/camelot_py-0.8.2-py3.8.egg/camelot/ext/ghostscript/__init__.py", line 90, in Ghostscript
return __Ghostscript(
File "Code/Camelot-dev/excalibur/.venv/lib/python3.8/site-packages/camelot_py-0.8.2-py3.8.egg/camelot/ext/ghostscript/__init__.py", line 39, in __init__
rc = gs.init_with_args(instance, args)
File "Code/Camelot-dev/excalibur/.venv/lib/python3.8/site-packages/camelot_py-0.8.2-py3.8.egg/camelot/ext/ghostscript/_gsprint.py", line 174, in init_with_args
raise GhostscriptError(rc)
127.0.0.1 - - [06/Aug/2020 12:54:50] "GET /workspaces/eee2199b-6de1-4d36-8131-abc25fcca6cf HTTP/1.1" 200 -
127.0.0.1 - - [06/Aug/2020 12:54:51] "GET /workspaces/eee2199b-6de1-4d36-8131-abc25fcca6cf HTTP/1.1" 200 -
127.0.0.1 - - [06/Aug/2020 12:54:51] "GET /workspaces/eee2199b-6de1-4d36-8131-abc25fcca6cf HTTP/1.1" 200 -
127.0.0.1 - - [06/Aug/2020 12:54:52] "GET /workspaces/eee2199b-6de1-4d36-8131-abc25fcca6cf HTTP/1.1" 200 -

```


Start with the split entry point in excalibur/tasks.py, then trace the Ghostscript call shown in camelot/ext/ghostscript/__init__.py and its _gsprint.py binding. Reproduce the failure on the reported Ubuntu and Ghostscript versions, and determine why processing remains stuck after the error. Done means PDF extraction completes or reports a clear failure instead of remaining in Processing.

Written by the indexing model from the issue text.