schema: Fix interface link state schema

In commit edd1295e1d I've introduced an
XML element that allows to configure state of the network interface
link. Somehow the RNG schema hunk ended up in a weird place in the
network schema definition. Move it to the right place and add a test
case.

Note that the link state is set up via the monitor at VM startup so I
originally didn't think of adding a test case.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1173468

docs/schemas/domaincommon.rng

@@ -2314,9 +2314,21 @@
         - the name of the script used to set up the binding
         - the target device used
         - boot order
+        - link state
     -->
   <define name="interface-options">
     <interleave>
+      <optional>
+        <element name="link">
+          <attribute name="state">
+            <choice>
+              <value>up</value>
+              <value>down</value>
+            </choice>
+          </attribute>
+          <empty/>
+        </element>
+      </optional>
       <optional>
         <element name="target">
           <attribute name="dev">

docs/schemas/network.rng

@@ -299,17 +299,6 @@
         <optional>
          <ref name="vlan"/>
         </optional>
-        <optional>
-          <element name="link">
-            <attribute name="state">
-              <choice>
-                <value>up</value>
-                <value>down</value>
-              </choice>
-            </attribute>
-            <empty/>
-          </element>
-        </optional>
 
         <!-- <ip> element -->
         <zeroOrMore>

tests/qemuxml2argvdata/qemuxml2argv-interface-driver.xml

@@ -39,6 +39,7 @@
       <mac address='52:54:00:e5:48:58'/>
       <model type='virtio'/>
       <driver ioeventfd='on' event_idx='on' queues='5'/>
+      <link state='up'/>
     </interface>
     <serial type='pty'>
       <target port='0'/>