Deactivate firewalld

[ghost]

Summary:
Deactivate default RHEL 7 firewalld service because it generates
firewall rules which are not compatible with eucanetd.

Reproducing:

1. Run cloud-in-a-box.sh on a server that is running firewalld
2. Observe that eucanetd is failing due to bad firewall rules

[euca-qa-eqs-tester]

Can one of the admins verify this patch?

[ghost]

@tbeckham in eucalyptus/recipes/default.rb there is code that is already trying to clear the firewall with iptables -F etc. but it will fail if firewalld is running because firewalld will be adding rules that conflict with the ones added by eucanetd. This change just turns off firewalld right before the default recipe tries to clear the firewall.

[ghost]

@tbeckham The documentation says to disable firewalld
https://docs.eucalyptus.com/eucalyptus/4.4.2/install-guide/rhel7_disable_firewalld.html