ftests: Add cgget test with '-g' <controller>:<cgroup> flag

ftests: Add cgget test with '-g' <controller>:<cgroup> flag

Add a test that exercises the '-g' <controller>:<cgroup> option
in cgget.  This test verifies the following cgget operation:

	$ cgget -g cpu:010cgget

-----------------------------------------------------------------
Test Results:
        Run Date:                          Feb 09 21:04:46
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
Timing Results:
        Test                                    Time (sec)
        ---------------------------------------------------------
        setup                                        20.73
        010-cgget-g_flag_controller_and_cgroup.py           0.60
        teardown                                      0.00
        ---------------------------------------------------------
        Total Run Time                               21.33

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>