Remove non-existant 'wiremode' attribute

The 'wiremode' attribute exists in a couple of Xen XML files, but no code has
ever parsed that value. It was later added to the RNG schema too, again despite
there not being any code which parses it.
Reviewed-by: NJim Fehlig <jfehlig@suse.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

docs/schemas/domaincommon.rng

@@ -3708,9 +3708,6 @@
         <optional>
           <attribute name="service"/>
         </optional>
-        <optional>
-          <attribute name="wiremode"/>
-        </optional>
         <optional>
           <attribute name="channel"/>
         </optional>

tests/xml2sexprdata/xml2sexpr-fv-parallel-tcp.xml

@@ -32,7 +32,7 @@
       <target dev='ioemu:hda'/>
     </disk>
     <parallel type='tcp'>
-      <source mode='connect' host='localhost' service='9999' wiremode='raw'/>
+      <source mode='connect' host='localhost' service='9999'/>
       <target port='0'/>
     </parallel>
     <graphics type='vnc' port='5917' keymap='ja'/>

tests/xml2sexprdata/xml2sexpr-fv-serial-tcp.xml

@@ -32,7 +32,7 @@
       <target dev='ioemu:hda'/>
     </disk>
     <serial type='tcp'>
-      <source mode='bind' host='localhost' service='9999' wiremode='raw'/>
+      <source mode='bind' host='localhost' service='9999'/>
       <target port='0'/>
     </serial>
     <graphics type='vnc' port='5917' keymap='ja'/>