pymongo still using "platform.linux_distribution()"

This issue relates to work performed on PYTHON-1346.  Which stats as an objective to remove the deprecated platform.linux_distribution() function.

However in review of the commit (https://github.com/mongodb/mongo-python-driver/commit/82c610a9f54d5af20d9b5b626189891d82216a4f) and the current driver src, the platform.linux_distribution() function is still present and active.

Please clarify if this is the expected observation, and if not, please replace the deprecated function (scheduled for removal in Python 3.8).