fix switch formatting

Signed-off-by: William Douglas <william.douglas@intel.com>
shared: Remove obsolete function pointers

This change removes function pointers for the daemon's get_value,
set_value and register_notification functions that are no longer
needed to call these functions.

Signed-off-by: William Douglas <william.douglas@intel.com>
shared: Assert status for get_value and set_value

Signed-off-by: William Douglas <william.douglas@intel.com>
test: Add tests for get_value, set_value and register_notification