Allow to manage or not TSO issue

We need to allow some flexibility with TSO issue and allow the end-user
to disable the management of TSO.

Since TSO issue only affects GRE tunnels, when running VXLAN we should
be able to not manage TSO issue. So let's add a new parameter to manage
or not this feature.

Why not using facter to detect the kernel & using neutron flags to
detect the tunneling mode? Because we want to be sure that we have a
real flexibility and allow end-user to use a specific kernel (with a fix
or not) and make the choice to enable or not TSO/GSO.

spec/classes/cloud_compute_hypervisor_spec.rb

@@ -316,6 +316,18 @@ describe 'cloud::compute::hypervisor' do
       end
     end
 
+    context 'when not managing TSO/GSO/GRO' do
+      before :each do
+        params.merge!( :manage_tso => false)
+      end
+      it 'ensure TSO script is not managed at boot' do
+        should_not contain_exec('enable-tso-script')
+      end
+      it 'do not start TSO script' do
+        should_not contain_exec('start-tso-script')
+      end
+    end
+
     context 'with RBD backend for instances and volumes on Debian plaforms' do
       before :each do
         facts.merge!( :osfamily => 'Debian',