Comment 14 for bug 1697209

Used patch from commit https://git.launchpad.net/maas/commit/?id=df9a79b9dba9c9beee8c2c272263085f5dc02bad to modify /usr/lib/python3/dist-packages/provisioningserver/kernel_opts.py, restarted associated services and solved the problem on MAAS 2.1.

It would be nice if the patch would be officially backported to 2.1 branch.