docs/qmp: Fix documentation of BLOCK_JOB_READY to match code

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

docs/qmp/qmp-events.txt

@@ -157,12 +157,20 @@ Emitted when a block job is ready to complete.
 
 Data:
 
-- "device": device name (json-string)
+- "type":     Job type (json-string; "stream" for image streaming
+                                     "commit" for block commit)
+- "device":   Device name (json-string)
+- "len":      Maximum progress value (json-int)
+- "offset":   Current progress value (json-int)
+              On success this is equal to len.
+              On failure this is less than len.
+- "speed":    Rate limit, bytes per second (json-int)
 
 Example:
 
 { "event": "BLOCK_JOB_READY",
-    "data": { "device": "ide0-hd1" },
+    "data": { "device": "drive0", "type": "mirror", "speed": 0,
+              "len": 2097152, "offset": 2097152 }
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
 
 Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR