Add actions to virDomainLifecycle enum

Xen supports on_crash actions coredump-{destroy,restart}.  libvirt
cannot parse config returned by xend that contains either of these
actions

xen52 # xm li -l test | grep on_crash
    (on_crash coredump-restart)
xen52 # virsh dumpxml test
error: internal error unknown lifecycle type coredump-restart

This patch adds a new virDomainLifecycleCrash enum and appends
the new options to existing destroy, restart, preserve, and
rename-restart options.

docs/formatdomain.html.in

@@ -366,6 +366,21 @@
         a new name</dd>
     </dl>
 
+    <p>
+      on_crash supports these additional
+      actions <span class="since">since 0.8.4</span>.
+    </p>
+
+    <dl>
+      <dt><code>coredump-destroy</code></dt>
+      <dd>The crashed domain's core will be dumped, and then the
+        domain will be terminated completely and all resources
+        released</dd>
+      <dt><code>coredump-restart</code></dt>
+      <dd>The crashed domain's core will be dumped, and then the
+        domain will be restarted with the same configuration</dd>
+    </dl>
+
     <h3><a name="elementsFeatures">Hypervisor features</a></h3>
 
     <p>

docs/schemas/domain.rng

@@ -1177,7 +1177,7 @@
       </optional>
       <optional>
         <element name="on_crash">
-          <ref name="offOptions"/>
+          <ref name="crashOptions"/>
         </element>
       </optional>
     </interleave>
@@ -1198,6 +1198,29 @@
       <value>rename-restart</value>
     </choice>
   </define>
+  <!--
+      Options when a domain crashes:
+      destroy: The domain is cleaned up
+      restart: A new domain is started in place of the old one
+      preserve: The domain will remain in memory until it is destroyed manually
+      rename-restart: a variant of the previous one but where the old domain is
+                      renamed before being saved to allow a restart
+      coredump-destroy: The crashed domain's core will be dumped, and then the
+                        domain will be terminated completely and all resources
+                        released
+      coredump-restart: The crashed domain's core will be dumped, and then the
+                        domain will be restarted with the same configuration
+    -->
+  <define name="crashOptions">
+    <choice>
+      <value>destroy</value>
+      <value>restart</value>
+      <value>preserve</value>
+      <value>rename-restart</value>
+      <value>coredump-destroy</value>
+      <value>coredump-restart</value>
+    </choice>
+  </define>
   <!--
       Specific setup for a qemu emulated character device.  Note: this
       definition doesn't fully specify the constraints on this node.