Fix naming of constant for disk event

All constants related to events should have a prefix of
VIR_DOMAIN_EVENT_

* include/libvirt/libvirt.h.in, src/qemu/qemu_domain.c:
  Rename VIR_DOMAIN_DISK_CHANGE_MISSING_ON_START to
  VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START

include/libvirt/libvirt.h.in

@@ -3069,12 +3069,12 @@ typedef void (*virConnectDomainEventBlockJobCallback)(virConnectPtr conn,
                                                       void *opaque);
 
 /**
- * virConnectDomainEventDisChangeReason:
+ * virConnectDomainEventDiskChangeReason:
  *
  * The reason describing why this callback is called
  */
 typedef enum {
-    VIR_DOMAIN_DISK_CHANGE_MISSING_ON_START = 0, /* oldSrcPath is set */
+    VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START = 0, /* oldSrcPath is set */
 } virConnectDomainEventDiskChangeReason;
 
 /**

src/qemu/qemu_domain.c

@@ -1652,7 +1652,7 @@ qemuDomainCheckDiskPresence(struct qemud_driver *driver,
                   disk->dst, vm->def->name, uuid, disk->src);
 
         event = virDomainEventDiskChangeNewFromObj(vm, disk->src, NULL, disk->info.alias,
-                                                   VIR_DOMAIN_DISK_CHANGE_MISSING_ON_START);
+                                                   VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START);
         if (event)
             qemuDomainEventQueue(driver, event);