[AIRFLOW-XXX] Avoid spamming the log from Airflow security manager

[feng-tao]

Make sure you have checked all steps below.

Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-XXX
  • In case you are fixing a typo in the documentation you can prepend your commit with [AIRFLOW-XXX], code changes always need a Jira issue.
  • In case you are proposing a fundamental code change, you need to create an Airflow Improvement Proposal(AIP).

Description

• Here are some details about my PR, including screenshots of any UI changes:
  Avoid spamming the log as these logs are used when developing the features. Now it will log by every gunicorn worker per every starts up.

Change it to debug level.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it.
  • When adding new operators/hooks/sensors, the autoclass documentation generation needs to be added.
  • All the public functions and the classes in the PR contain docstrings that explain what it does
  • If you implement backwards incompatible changes, please leave a note in the Updating.md so we can assign it to a appropriate release

Code Quality

• Passes flake8

[feng-tao]

cc @ashb
this is part of today's pr discussion. Let me know if I need to create a jira.

[Fokko]

Collecting flake8
  Cache entry deserialization failed, entry ignored
  Using cached https://files.pythonhosted.org/packages/e9/76/b915bd28976068a9843bf836b789794aa4a8eb13338b23581005cd9177c0/flake8-3.7.7-py2.py3-none-any.whl
Collecting pycodestyle<2.6.0,>=2.5.0 (from flake8)
  Cache entry deserialization failed, entry ignored
  Using cached https://files.pythonhosted.org/packages/0e/0c/04a353e104d2f324f8ee5f4b32012618c1c86dd79e52a433b64fceed511b/pycodestyle-2.5.0-py2.py3-none-any.whl
Collecting mccabe<0.7.0,>=0.6.0 (from flake8)
  Cache entry deserialization failed, entry ignored
  Using cached https://files.pythonhosted.org/packages/87/89/479dc97e18549e21354893e4ee4ef36db1d237534982482c3681ee6e7b57/mccabe-0.6.1-py2.py3-none-any.whl
Collecting entrypoints<0.4.0,>=0.3.0 (from flake8)
  Cache entry deserialization failed, entry ignored
  Using cached https://files.pythonhosted.org/packages/ac/c6/44694103f8c221443ee6b0041f69e2740d89a25641e62fb4f2ee568f2f9c/entrypoints-0.3-py2.py3-none-any.whl
Collecting pyflakes<2.2.0,>=2.1.0 (from flake8)
  Cache entry deserialization failed, entry ignored
  Using cached https://files.pythonhosted.org/packages/84/f2/ed0ffb887f8138a8fe5a621b8c0bb9598bfb3989e029f6c6a85ee66628ee/pyflakes-2.1.1-py2.py3-none-any.whl
Installing collected packages: pycodestyle, mccabe, entrypoints, pyflakes, flake8
Successfully installed entrypoints-0.3 flake8-3.7.7 mccabe-0.6.1 pycodestyle-2.5.0 pyflakes-2.1.1
40.21s$ flake8
./airflow/www/security.py:201:111: E501 line too long (111 > 110 characters)
The command "flake8" exited with 1.

[feng-tao]

thanks @Fokko , just updated the pr.

[feng-tao]

ping @Fokko @ashb

[feng-tao]

PTAL @Fokko @ashb @XD-DENG @ashb

[XD-DENG]

LGTM.