dtdphi: changes to allow dag to run end to end.

Also @surabhi.sachdev, potentially @alvin.li should look. These changes might make more sense if you consider the full diff relative to e30b5358 (the commit before first dtdphi proposed changes).

https://ldas-jobs.gwave.ics.psu.edu/~ryan.magee/dtdphi.patch

This is certainly not the only way to fix the issues I was having, but it is one way. I'd like this merged if everyone agrees it looks sensible, though at this point I'm tempted to open an issue to do some cleanup on these files and this code in general.