Fix conditional in single-instance firewall
Fix conditional in single-instance firewall

In a single-instance install, firewall port opening is failing:

```
TASK [lsnr-create : Open listener port in firewall] ****************************
fatal: [mfielding-ora1]: FAILED! => {"msg": "The conditional check 'disable_firewall|bool is false' failed. The error was: template error while templating string: no test named 'false'. String: {% if disable_firewall|bool is false %} True {% else %} False {% endif %}\n\nThe error appears to be in '/home/mfielding/git/nofail/roles/lsnr-create/tasks/main.yml': line 16, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: Open listener port in firewall\n  ^ here\n"}
```

Fixing the check to avoid the error

google/bms-toolkit,google/bms-toolkit