Avoid refreshing firewall rules unnecessarily.

Adds a parameter to refresh_firewall allowing an array of ports to
be passed.  If an array is passed then the firewall will be refreshed
only for those ports.  If not passed, it will still refresh all
ports as it did before.

Change-Id: I539a135dbc3861e31cbb5c69cef0ff8c0f834527
Fixes: Bug #1202328
Merge "Avoid refreshing firewall rules unnecessarily."