150a0cc STAP: Only print transaction statistics if the script caught some transactions

1 file Authored by jhrozek 7 years ago, Committed by lslebodn 7 years ago,
    STAP: Only print transaction statistics if the script caught some transactions
    
    If the script measured an 'id' run from the cache, there would be no
    transactions and dereferencing the aggrefate would throw an error.
    
    Reviewed-by: Fabiano FidĂȘncio <fidencio@redhat.com>