[BUG] gitfs_provider ignored with pygit2 installed

[remyd1]

Description
In the gitfs documentation, it is said that gitfs_provider should be used when both pygit2 and gitpython are installed. It seems that it does not work.

Uninstalling pygit2 solves this issue.

Versions Report

After uninstalling pygit2 (1.2.1):

salt --versions-report

Salt Version: Salt: 3000.3

Dependency Versions:
cffi: 1.14.0
cherrypy: Not Installed
dateutil: 2.6.1
docker-py: Not Installed
gitdb: 2.0.3
gitpython: 2.1.8
Jinja2: 2.10
libgit2: Not Installed
M2Crypto: Not Installed
Mako: Not Installed
msgpack-pure: Not Installed
msgpack-python: 0.5.6
mysql-python: Not Installed
pycparser: 2.20
pycrypto: 2.6.1
pycryptodome: Not Installed
pygit2: Not Installed
Python: 3.6.9 (default, Apr 18 2020, 01:56:04)
python-gnupg: 0.4.1
PyYAML: 3.12
PyZMQ: 16.0.2
smmap: 2.0.3
timelib: Not Installed
Tornado: 4.5.3
ZMQ: 4.2.5

System Versions:
dist: Ubuntu 18.04 bionic
locale: ANSI_X3.4-1968
machine: x86_64
release: 5.4.41-1-pve
system: Linux
version: Ubuntu 18.04 bionic

Additional context
I was working on my issue here.

[xeacott]

Thanks lol @remyd1 so I brought up your issues in our internal chat because there definitely seems to be something going on here with the opts, having gitfs providers, and then actually using them. we'll see what resolution we can bring, but is there a way to condense all your tickets into a single one? Sorry, I realize that's a big ask but I'll let you decide. 😄

[sagetherage]

I like having the docs updates in another ticket -- we can keep it as is.