When registering a repository with Scalar to get the latest opinionated configuration, the 'scalar register' command will also set up background maintenance. This is a recommended feature for most user scenarios. However, this is not always recommended in some scenarios where background modifications may interfere with foreground activities. Specifically, setting up a clone for use in automation may require doing certain maintenance steps in the foreground that could become blocked by concurrent background maintenance operations. Allow the user to specify --no-maintenance to 'scalar register'. This requires updating the method prototype for register_dir(), so use the default of enabling this value when otherwise specified. Signed-off-by: Derrick Stolee <stolee@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>