Revert "Run stack_check after DB migrations and seeds (#453)" (#454)

This reverts commit f445c39.

We can now run the stack checker before migrations as per
cloudfoundry/cloud_controller_ng#3925.

This is an improvement as we want to fail the stack checker before any
migrations have run so that we are not in a state where migrations
have run but the deployment has failed

Co-authored-by: Sam Gunaratne <sam.gunaratne@broadcom.com>

jobs/cloud_controller_ng/templates/pre-start.sh.erb

@@ -142,14 +142,14 @@ function main {
   start_bosh_dns_or_consul
   setup_directories
   <% if spec.bootstrap && p('cc.run_prestart_migrations') %>
+  stack_check
   perform_migration
   seed_db
     <% if p('cc.database_encryption.skip_validation') %>
     echo "Skipping DB encryption validation"
     <% else %>
     validate_encryption_keys
     <% end %>
-  stack_check
   <% else %>
   echo "Skipping DB migrations and seeds"
   <% end %>