qemu: command: Use XML based disk bus convertor in error message

The qemu driver has an internal implementation for converting disk bus
to string for use with qemu. This should not be used in error messages
though as we want to report the string based on the XML value.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
ACKed-by: NEric Blake <eblake@redhat.com>

src/qemu/qemu_command.c

@@ -1303,7 +1303,7 @@ qemuCheckDiskConfig(virDomainDiskDefPtr disk,
             disk->bus != VIR_DOMAIN_DISK_BUS_SCSI) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("disk device='lun' is not supported for bus='%s'"),
-                           virDomainDiskQEMUBusTypeToString(disk->bus));
+                           virDomainDiskBusTypeToString(disk->bus));
             return -1;
         }