roles/common: Use "interface" instead of "alias" to get interface name in firewalld template

Signed-off-by: Alan Orth <alan.orth@gmail.com>

roles/common/templates/public.xml.j2

@@ -1,7 +1,7 @@
 <zone>
     <short>Public</short>
     <description>For use in public areas. You do not trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.</description>
-    <interface name="{{ ansible_default_ipv4.alias }}"/>
+    <interface name="{{ ansible_default_ipv4.interface }}"/>
 
     {# ssh rules #}
     <rule family="ipv4">