Return a value if exceptions are raised in server uninstall
    
    The AdminTool class purports to "call sys.exit() with the return
    value" but most of the run implementations returned no value, or
    the methods they called returned nothing so there was nothing to
    return, so this was a no-op.
    
    The fix is to capture and bubble up the return values which will
    return 1 if any exceptions are caught.
    
    This potentially affects other users in that when executing the
    steps of an installer or uninstaller the highest return code
    will be the exit value of that installer.
    
    Don't use the Continuous class because it doesn't add any
    value and makes catching the exceptions more difficult.
    
    https://pagure.io/freeipa/issue/7330
    
    Signed-off-by: Rob Crittenden rcritten@redhat.com
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>