qemu: Register qemuProcessCleanupMigrationJob after Begin phase

The callback will properly cleanup non-p2p migration job in case the
migrating domain dies between Begin and Perform while the client which
controls the migration is not cooperating (normally the API for the next
migration phase would handle this).

The same situation can happen even after Prepare and Perform phases, but
they both already register a suitable callback, so no fix is needed
there.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>

src/qemu/qemu_migration.c

@@ -2902,6 +2902,8 @@ qemuMigrationSrcBegin(virConnectPtr conn,
         if (virCloseCallbacksSet(driver->closeCallbacks, vm, conn,
                                  qemuMigrationAnyConnectionClosed) < 0)
             goto endjob;
+
+        qemuDomainCleanupAdd(vm, qemuProcessCleanupMigrationJob);
     }
 
     ret = g_steal_pointer(&xml);