No cmd fail transcript

[crotwell]

fix #1207

Not sure this is the best way to go about it, but seems to at least fail now on non-existent commands

[kmvanbrunt]

@crotwell Thanks for working on this. However, we need an approach that captures all data written to the stderr stream, not just what's printed by perror(). I'm closing this since #1185 already documents the issue. I'll begin work on that ticket soon.