Added nsslapd-logging-hr-timestamps-enabled attribute in _SINGLE_VALUE_OVERRIDE table
    
    In ipa-healthcheck ds-related tests i.e
    test_ipahealthcheck.py::TestIpaHealthCheck::test_ipahealthcheck_ds_configcheck
    there exists a scenario of modifying the "nsslapd-logging-hr-timestamps-enabled" attribute to off
    
    The tests are failing with the below error
    "ipalib.errors.MidairCollision: change collided with another change"
    
    The test audit log displays that the attribute is deleted first and then added.
    changetype: modify
    delete: nsslapd-logging-hr-timestamps-enabled
    nsslapd-logging-hr-timestamps-enabled: on
    -
    add: nsslapd-logging-hr-timestamps-enabled
    nsslapd-logging-hr-timestamps-enabled: off
    
    Adding the nsslapd-logging-hr-timestamps-enabled attribute in _SINGLE_VALUE_OVERRIDE table
    to check if we generate a replace instead of add and delete.
    
    Signed-off-by: Sudhir Menon <sumenon@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>