Option to disable firewall opening

[audunmg]

Great role, would be even better if the firewall opening is optional.

I prefer to open omsa port only to a certain subnet or not at all in certain situations, I'm sure you understand :)

[jose-delarosa]

@feitingen, I haven't updated this role in a while, I will add it to my list of things to do. I will add a variable, something like FIREWALL_OPEN and then a user can more easily set it to True or False.