Unit tests for neutron::plugins::ovs::opendaylight is broken on ubnutu focal

Since we replaced ubuntu bionic with ubuntu focal, we observe the following error in unit tests

~~~
1) neutron::plugins::ovs::opendaylight on ubuntu-18.04-x86_64 behaves like neutron plugin opendaylight ovs with TLS and no CA cert is expected to contain Vs_ssl[system] with ensure => "present", key_file => "dummy.pem", cert_file => "dummy.crt", bootstrap => true and before => "Exec[Set OVS Manager to OpenDaylight]"
   Failure/Error:
     it {should contain_vs_ssl('system').with(
       'ensure' => 'present',
       'key_file' => 'dummy.pem',
       'cert_file' => 'dummy.crt',
       'bootstrap' => true,
       'before' => 'Exec[Set OVS Manager to OpenDaylight]'
     )}

   Errno::EISDIR:
     Is a directory @ io_fread - /home/zuul/workspace/spec/fixtures/manifests
   Shared Example Group: "neutron plugin opendaylight ovs" called from ./spec/classes/neutron_plugins_ovs_opendaylight_spec.rb:234
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:158:in `read'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:158:in `site_pp_str'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:23:in `build_code'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:105:in `block in load_catalogue'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:410:in `with_vardir'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:85:in `load_catalogue'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/example/class_example_group.rb:7:in `catalogue'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/support.rb:14:in `block in subject'
   # ./.bundled_gems/gems/rspec-puppet-2.8.0/lib/rspec-puppet/matchers/create_generic.rb:84:in `matches?'
   # ./spec/classes/neutron_plugins_ovs_opendaylight_spec.rb:78:in `block (4 levels) in <top (required)>'
~~~

https://zuul.opendev.org/t/openstack/build/dd82860f0166458c96cf0aebeecb1205