ftests: Add a test to create a default systemd scope via cgcreate

ftests: Add a test to create a default systemd scope via cgcreate

Add a test to create a systemd scope via the cgcreate command
line tool.  The scope is set as the default and used to create
a child cgroup.

-----------------------------------------------------------------
Test Results:
        Run Date:                          Apr 10 21:39:10
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
        Test                                          Time (sec)
        --------------------------------------------------------
        setup                                               0.00
        079-sudo-cgcreate_default_systemd_scope.py          5.06
        teardown                                            0.00
        --------------------------------------------------------
        Total Run Time                                      5.06

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
(cherry picked from commit 8e29c7282c956bfb75847f6d46f55668be786817)