4e87164 zfs: Resolve RESOURCE_LEAK

Authored and Committed by John Ferlan 8 years ago
    zfs: Resolve RESOURCE_LEAK
    
    Found by my Coverity checker - virCheckFlags call could return -1, but
    not virCommandFree(destroy_cmd).
    
    Signed-off-by: John Ferlan <jferlan@redhat.com>