block: add block-job-complete

While streaming can be dropped as soon as it progressed through the whole
image, mirroring needs to be completed manually for two reasons: 1) so that
management knows exactly when the VM switches to the target; 2) because
for other use cases such as replication, we may leave the operation running
for the whole life of the virtual machine.

Add a new block job command that manually completes background operations.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5ba8c48..4f9c711 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -843,6 +843,11 @@
         .mhandler.cmd_new = qmp_marshal_input_block_job_resume,
     },
     {
+        .name       = "block-job-complete",
+        .args_type  = "device:B",
+        .mhandler.cmd_new = qmp_marshal_input_block_job_complete,
+    },
+    {
         .name       = "transaction",
         .args_type  = "actions:q",
         .mhandler.cmd_new = qmp_marshal_input_transaction,