[Patch] - Bug #7580 - uwsgi + nginx db backup does not work

Hello,

Please find the attached path which fixes the error while taking backup
using pgadmin configured using uWSGI & NGINX.
Actually error is -

2022-09-01 15:17:29,897: ERROR pgadmin: preexec_fn not
supported within subinterpreters
Traceback (most recent call last):
File "/opt/pgadmin/venv/lib/python3.8/site-packages/pgadmin4/pgadmin/tools/backup/__init__.py",
line 451, in create_backup_objects_job
p.start()
File "/opt/pgadmin/venv/lib/python3.8/site-packages/pgadmin4/pgadmin/misc/bgprocess/processes.py",
line 336, in start
p = self.get_process_output(cmd, env)
File "/opt/pgadmin/venv/lib/python3.8/site-packages/pgadmin4/pgadmin/misc/bgprocess/processes.py",
line 374, in get_process_output
p = Popen(
File "/usr/lib/python3.8/subprocess.py", line 858, in __init__
self._execute_child(args, executable, preexec_fn, close_fds,
File "/usr/lib/python3.8/subprocess.py", line 1639, in _execute_child
self.pid = _posixsubprocess.fork_exec(
RuntimeError: preexec_fn not supported within subinterpreters

Which is causing due to change in version 3.8 - 'The *preexec_fn* parameter
is no longer supported in subinterpreters.'. (Refer this link
<https://docs.python.org/3/library/subprocess.html>)

I have tested the attached patch with dev env on Mac & centos platform.
Also tested with installed pgadmin version with pip by manipulating
corresponding files.

Thanks,
Yogesh Mahajan
EnterpriseDB