schemas: domaincaps: Add schema for CPU 'blockers'

Due to broken 'virschematest' commit f4dc248a95
forgot to introduce schema for the new element.

Fixes: f4dc248a95
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/conf/schemas/domaincaps.rng

@@ -174,6 +174,20 @@
           </attribute>
           <text/>
         </element>
+        <optional>
+          <element name="blockers">
+            <attribute name="model">
+              <text/>
+            </attribute>
+            <oneOrMore>
+              <element name="feature">
+                <attribute name="name">
+                  <text/>
+                </attribute>
+              </element>
+            </oneOrMore>
+          </element>
+        </optional>
       </zeroOrMore>
     </element>
   </define>