Remove unneccessary isoToDate function
[CQ] Let's celebrate the recent 6 year anniversary of making isoToData unnecessary by getting it out of the code
Prior to July 2014 the following would fail
because the fetch format for dates was invalid for save.
However, that all changed once this was merged https://github.com/civicrm/civicrm-packages/commit/283da6111677fc2b0176902b4c9a5cbcf668a258
Except for the bits that provide handling for it still litter our code