ipatests: generic uninstall should call ipa server-del
    
    At the end of any integration test, the method uninstall is called and
    uninstalls master, replicas and clients.
    Usually the master is the CA renewal master and DNSSec master, and
    uninstallation may fail.
    This commits modifies the uninstall method in order to:
    - call 'ipa server-del replica' before running uninstall on a replica
    - uninstall the replicas before uninstalling the master
    
    Fixes: https://pagure.io/freeipa/issue/7985
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Sergey Orlov <sorlov@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>