blockjob: return appropriate event and info

Handle the new type of block copy event and info.  Of course,
this patch does nothing until a later patch actually allows the
creation/abort of a block copy job.

* include/libvirt/libvirt.h.in (VIR_DOMAIN_BLOCK_JOB_READY): New
block job status.
* src/libvirt.c (virDomainBlockRebase): Document the event.
* src/qemu/qemu_monitor_json.c (eventHandlers): New event.
(qemuMonitorJSONHandleBlockJobReady): New function.
(qemuMonitorJSONGetBlockJobInfoOne): Translate new job type.
(qemuMonitorJSONHandleBlockJobImpl): Handle new event and job type.
* src/qemu/qemu_process.c (qemuProcessHandleBlockJob): Recognize
the event to minimize snooping.
* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Snoop a successful
info query to save effort on a pivot request.

include/libvirt/libvirt.h.in

@@ -4120,6 +4120,7 @@ typedef enum {
     VIR_DOMAIN_BLOCK_JOB_COMPLETED = 0,
     VIR_DOMAIN_BLOCK_JOB_FAILED = 1,
     VIR_DOMAIN_BLOCK_JOB_CANCELED = 2,
+    VIR_DOMAIN_BLOCK_JOB_READY = 3,
 
 #ifdef VIR_ENUM_SENTINELS
     VIR_DOMAIN_BLOCK_JOB_LAST