fence_scsi_test: rewrite to more accurately test
    
    The old fence_scsi_test tool was far too simple to adequately
    test it a devices was capable of being used with fence_scsi.
    This rewrite should adequately test all requirements, such as
    support for "preempt-and-abort" subcommand. This script will
    also verify that each command worked as expected.
    
    Resolves: rhbz#603838
    
    Signed-off-by: Ryan O'Hara <rohara@redhat.com>