schema: support 'default' cache mode

The docs claims the cache attribute of the disk <driver>
element supports 'default' as one of its permissible values,
but such configuration fails virt-xml-validate. Add 'default'
as one of the cache attribute choices in domaincommon.rng.

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 8c6287d8bff59010734dc701caf86a1f3a25ad2d..0eb1e5ad727606ad848db8e77b909d43ef056c1e 100644 (file)
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1606,6 +1606,7 @@
   <define name="driverCache">
     <attribute name="cache">
       <choice>
+        <value>default</value>
         <value>none</value>
         <value>writeback</value>
         <value>writethrough</value>