Revert "Add support for <option> tag in network config"

This reverts commit 383ebc4694.

We decided the xml for this feature needed more thought to make sure
we are doing it the best way, in particular wrt option values that
have multiple items.

tests/networkxml2confdata/nat-network.conf

@@ -12,11 +12,6 @@ bind-dynamic
 interface=virbr0
 dhcp-range=192.168.122.2,192.168.122.254
 dhcp-no-override
-dhcp-option=42,192.168.122.20
-dhcp-option=23,50
-dhcp-option=40,libvirt
-dhcp-option=252,"\n"
-dhcp-option=253," leading and trailing spaces "
 dhcp-leasefile=/var/lib/libvirt/dnsmasq/default.leases
 dhcp-lease-max=253
 dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile

tests/networkxml2confdata/nat-network.xml

@@ -8,11 +8,6 @@
       <range start='192.168.122.2' end='192.168.122.254' />
       <host mac='00:16:3e:77:e2:ed' name='a.example.com' ip='192.168.122.10' />
       <host mac='00:16:3e:3e:a9:1a' name='b.example.com' ip='192.168.122.11' />
-      <option number='42' value='192.168.122.20'/>
-      <option number='23' value='50'/>
-      <option number='40' value='libvirt'/>
-      <option number='252' value='\n'/>
-      <option number='253' value=' leading and trailing spaces '/>
     </dhcp>
   </ip>
   <ip family='ipv4' address='192.168.123.1' netmask='255.255.255.0'>