Chef warning when /bin/su is a symlink

[sean-nixon]

Describe the bug
On some distributions, /bin/su is a symlink. Running the latest version of this cookbook on such systems results in a warning that manage_symlink_source is not set and that it will not be enabled by default in a future release (resulting in broken behavior).

Expected behavior
Running this cookbook should not result in deprecation warnings on systems where /bin/su is a symlink and will continue to function properly on future releases of Chef.

Actual behavior

file[/bin/su] action create[2020-05-21T00:40:00+00:00] WARN: File /bin/su managed by file[/bin/su] is really a symlink (to /usr/bin/su). Managing the source file instead.
[2020-05-21T00:40:00+00:00] WARN: Disable this warning by setting `manage_symlink_source true` on the resource
[2020-05-21T00:40:00+00:00] WARN: In a future release, 'manage_symlink_source' will not be enabled by default

OS / Environment

SLES 12 SP4

Chef Version

Chef Infra Client: 15.10.12

Cookbook Version

4.0.0