ConfigItem executes parent->takeChild(0)

while

ConfigList executes parent->takeTopLevelItem(0)
Signed-off-by: Boris Barbulovski <bbarbulovski@gmail.com>
Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: Michal Marek <mmarek@suse.com>