Add missing break in LXC loop device setup

When setting up disks with loop devices for LXC, one of the
switch cases was missing a 'break' causing it to fallthrough
to an error condition.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/lxc/lxc_controller.c

@@ -448,6 +448,7 @@ static int virLXCControllerSetupLoopDevices(virLXCControllerPtr ctrl)
             fd = virLXCControllerSetupLoopDeviceDisk(disk);
             if (fd < 0)
                 goto cleanup;
+            break;
 
         default:
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,