Drop the sshca sign policy moved block

modules/vault_cluster/state_migrations.tf

@@ -338,12 +338,6 @@ moved {
   to   = module.vault_policy["sshca/sign/host"].vault_policy.this
 }
 
-# The SSH host signing policy is named after the sshca role it grants (signhost)
-moved {
-  from = module.vault_policy["sshca/sign/host"].vault_policy.this
-  to   = module.vault_policy["sshca/sign/signhost"].vault_policy.this
-}
-
 moved {
   from = vault_policy.policies["sys/sys_audit_read"]
   to   = module.vault_policy["sys/audit/read"].vault_policy.this