Fix a bug where all OptionValue objects had the same underlying forwardings.
Review Request #1229 - Created Oct. 28, 2014 and submitted
|dturner-tw, ity, patricklaw|
This wasn't seen earlier because in practice all tasks migrated so far had
disjoint option names.
This was exposed when I migrated two unrelated tasks that happened to have
an identically named option (--skip).
Verified that this fixes the name collision issue that triggered its discovery in the first place.