Remove unsupported network platforms

[mhashizume]

This needs testing but I'd like to get this in before the next major release of beaker-puppet.

[joshcooper]

The tests are failing on this call to File.read

beaker-puppet/lib/beaker-puppet/install_utils/foss_utils.rb

Lines 1102 to 1104 in 04f07b6

	if host['platform'].variant =~ /^(ubuntu|debian)$/
	# Bypass signing checks on this repo and its packages
	original_contents = File.read(repo)

This seems to fix it

--- a/spec/beaker-puppet/install_utils/foss_utils_spec.rb
+++ b/spec/beaker-puppet/install_utils/foss_utils_spec.rb
@@ -864,6 +864,8 @@ describe ClassMixedWithDSLInstallUtils do
         allow(rez).to receive(:exit_code) { 0 }
         allow(subject).to receive(:link_exists?).and_return(true)
         expect(subject).to receive(:scp_to).with(host, repo_config, /.*/).ordered
+        allow(File).to receive(:read).and_call_original
+        allow(File).to receive(:read).with(repoconfig).and_return('')
         subject.install_puppetlabs_dev_repo host, package_name, package_version
       end
     end