Rename iolimit to blockio.

After discussion with DB we decided to rename the new iolimit
element as it creates the impression it would be there to
limit (i.e. throttle) I/O instead of specifying immutable
characteristics of a block device.
This is also backed by the fact that the term I/O Limits has
vanished from newer storage admin documentation.

Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

docs/formatdomain.html.in

@@ -1288,7 +1288,7 @@
       <driver name='qemu' type='raw'/>
       <source dev='/dev/sda'/>
       <geometry cyls='16383' heads='16' secs='63' trans='lba'/>
-      <iolimits logical_block_size='512' physical_block_size='4096'/>
+      <blockio logical_block_size='512' physical_block_size='4096'/>
       <target dev='hda' bus='ide'/>
     </disk>
   </devices>
@@ -1657,8 +1657,8 @@
             BIOS-Translation-Modus (none, lba or auto)</dd>
         </dl>
       </dd>
-      <dt><code>iolimits</code></dt>
-      <dd>If present, the <code>iolimits</code> element allows
+      <dt><code>blockio</code></dt>
+      <dd>If present, the <code>blockio</code> element allows
         to override any of the block device properties listed below.
         <span class="since">Since 0.10.2 (QEMU and KVM)</span>
         <dl>

docs/schemas/domaincommon.rng

@@ -890,7 +890,7 @@
         <ref name="geometry"/>
       </optional>
       <optional>
-        <ref name="diskIoLimits"/>
+        <ref name="diskBlockIo"/>
       </optional>
     </interleave>
   </define>
@@ -1116,8 +1116,8 @@
       </optional>
     </element>
   </define>
-  <define name="diskIoLimits">
-    <element name="iolimits">
+  <define name="diskBlockIo">
+    <element name="blockio">
       <optional>
         <attribute name="logical_block_size">
           <data type="integer"/>