ipatests: Take otptoken import test out of execution
    
    The issue reported in ticket [1] hasn't been solved yet.
    
    This patch prevents the test cases for OTP import being run.
    The change is intended as a *temporary* workaround until
    proper fix for the issue is introduced.
    
    [1] https://fedorahosted.org/freeipa/ticket/5192
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>