Right now we don't officialy support LinuxMint as our
documentation says [1], it seems LinuxMint is a relict
and got forgotten over time.
This patch removes LinuxMint from the code in order not to
confuse users.
[1] https://docs.openstack.org/devstack/latest/
Closes-Bug: #1983427
Change-Id: Ie1ced25f89389494b28a7b2e9bb1c4273e002dd5