pybind/mgr/*: fix config_notify handling of default values

pybind/mgr/*: fix config_notify handling of default values

The default values are handled by mgr_module.py's _get_module_option();
the or here means that we break any non-true (0, false, none) value and
override it with the default.

https://tracker.ceph.com/issues/43746
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 5ace82e65c72847fb875fc01c419937a26a59d70)

Conflicts:
	src/pybind/mgr/cephadm/module.py
- nautilus has no "cephadm" module. It does have an "orchestrator_cli"
  module but it doesn't contain the code being patched
	src/pybind/mgr/hello/module.py
- nautilus has a "hello" module, but it doesn't contain the code being
  patched