Fix style checks failure

[florimondmanca]

What does this PR do?

Fixes an issue with import styles that made style checks fail.

Motivation

Made CI in #6107 fail, see job logs: https://dev.azure.com/datadoghq/integrations-core/_build/results?buildId=11268&view=logs&jobId=a99fe294-74e6-5626-8ad8-bf38f5618435&j=a99fe294-74e6-5626-8ad8-bf38f5618435&t=e13d20aa-3dd4-5442-c1fb-77fea3251b6f

style run-test: commands[2] | isort --check-only --diff --recursive .
ERROR: /home/vsts/work/1/s/gunicorn/datadog_checks/gunicorn/gunicorn.py Imports are incorrectly sorted.
--- /home/vsts/work/1/s/gunicorn/datadog_checks/gunicorn/gunicorn.py:before	2020-03-24 14:58:30.631090
+++ /home/vsts/work/1/s/gunicorn/datadog_checks/gunicorn/gunicorn.py:after	2020-03-24 15:05:05.691401
@@ -15,7 +15,6 @@
 import psutil
 
 from datadog_checks.base import AgentCheck
-
 # project
 from datadog_checks.base.utils.subprocess_output import get_subprocess_output
 
ERROR: InvocationError for command /home/vsts/work/1/s/gunicorn/.tox/style/bin/isort --check-only --diff --recursive . (exited with code 1)

Additional Notes

Cleanup for #6088

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached

[codecov]

Codecov Report

Merging #6134 into master will increase coverage by 4.67%.
The diff coverage is n/a.

Impacted Files	Coverage Δ
gunicorn/datadog_checks/gunicorn/gunicorn.py	84.46% <ø> (ø)
envoy/tests/test_parser.py
network/datadog_checks/network/network.py
gearmand/datadog_checks/gearmand/__init__.py
...nmetrics/datadog_checks/openmetrics/openmetrics.py
datadog_checks_dev/datadog_checks/dev/errors.py
haproxy/tests/common.py
coredns/tests/conftest.py
sqlserver/tests/common.py
disk/datadog_checks/disk/__about__.py
... and 818 more