re-importing rancher2_cluster_template confuses template revisions

[ninjaslothx]

I was getting a issue similar to #365 when try to add in additional template revisions.
I built the provider off the master branch and experienced

Error: rpc error: code = Unavailable desc = transport is closing
panic: runtime error: invalid memory address or nil pointer dereference

A user in the above issue mentioned he changed computer and it went away.
I tried this to no avail but am using shared s3 state storage, so thought it might pay to delete the resource and re-import it

tf state rm rancher2_cluster_template.testing

tf import rancher2_cluster_template.testing cattle-global-data:ct-xhq5b

Once imported I went to check on my rpc error, but noticed that the import had caused terraform to try to swap around the template_revisions.
You can see v2 wanted to become v1, and vice versa.
Along with changing any config differences and the cluster_template_revision_id on the cluster which was referenced using the v1 index.

rancher2_cluster_template.testing.template_revisions.0.id

Changes only:

  ~ resource "rancher2_cluster" "testing" {
      ~ cluster_template_revision_id            = "cattle-global-data:ctr-xb8zj" -> "cattle-global-data:ctr-2qvxf"
      

  ~ resource "rancher2_cluster_template" "testing" {

      ~ template_revisions {
          ~ default             = false -> true
          ~ name                = "v2" -> "v1"
          ~ cluster_config {
              ~ rke_config {
                  ~ private_registries {
                      + password   = (sensitive value)
                    }
              ~ scheduled_cluster_scan {
                  ~ enabled = true -> false
                }

      ~ template_revisions {
          ~ default             = true -> false

          ~ name                = "v1" -> "v2"

          ~ cluster_config {
              ~ rke_config {
                  ~ private_registries {          
                      + password   = (sensitive value)
                    }

This then causes issues for obvious reasons, but also becomes an illegal operation as you are not allowed to update a template that is in use by the cluster.
Unsure if there is a better way to handle this import.

[rawmind0]

@ninjaslothx the issue has been reproduced. PR #395 includes a patch to address it

[rawmind0]

PR merged on master and will be available on next release. Please, reopen issue if needed.