7635728 otptoken_yubikey.py: Removed traceback when package missing.

1 file Authored by tdudlak 6 years ago, Committed by tkrizek 6 years ago,
    otptoken_yubikey.py: Removed traceback when package missing.
    
    IPA should suggest user to install dependent packages instead
    of throwing traceback. To work with IPA and Yubikey, packages
    libyubikey(not in official RHEL repo) and libusb are required.
    
    Resolves: https://pagure.io/freeipa/issue/6979
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>