Add a new option immediate= to immediately apply a permanent change

Currently, either you apply the change in the configuration
of firewalld ( without permanent=True ), or you apply it live.
I most of the time want to do the 2 at the same time, ie open the
port ( so I can use the service ) and make sure it stay open on reboot.
Merge pull request #1 from mscherer/devel

Add a new option immediate= to immediately apply a permanent change