Shared FileSystem deploy fails with NPE #13837

problem

Deploy Shared FileSystem loops through a shuffled list of supported hypervisors to find the systemVM template.
If one of the hypervisors (like External) don't have the systemVM template, instead of continuing to other hypervisors, it tries to access tempalte.getId() and throws NPE.

It only happens when the External hypervisor is present before any valid (KVM, VMware) hypervisor in the shuffled list. So this issue is intermittent.

versions

4.22.0

The steps to reproduce the bug

1. Add an external hypervisor like Proxmox/Maas/HyperV
2. Create a Shared FileSystem
3. It errors out with NPE intermittently
   ...

What to do about it?

SharedFS should only loop through supported Hypervisors (KVM, VMware and XenServer).
And if the template is not found, instead of throwing NPE it should continue to the next hypervisor in the list.