Fixed the cli failures in jenkins - user,content_view,medium and partition-table test

please review it 
thanks

The tests fixed are as follows : 
tests.foreman.cli.test_partitiontable.TestPartitionTableDelete.test_removeoperatingsystem_ptable
tests.foreman.cli.test_user.User.test_positive_create_user_4_1___________________example_com 
tests.foreman.cli.test_contentviews.TestContentView.test_cv_publish_composite
tests.foreman.cli.test_medium.TestMedium.test_removeoperatingsystem_medium