Delta option on Views filter does not work for end dates

Problem/Motivation

The delta option on filters in Views does not work for end dates. Setting "Add multiple value identifier" to "Yes" simply does not do anything.

A few hours of debugging shows that the problem is caused by the way $real_field_name is calculated when setting the id and delta fields on the Views query object. Instead of stripping '_value2' it only strips '_value', thus leaving '2'.

Proposed resolution

The solution is quite simple as per the attached patch.

-      $real_field_name = str_replace(array('_value', '_value2'), '', $this->real_field);
+      $real_field_name = str_replace(array('_value2', '_value'), '', $this->real_field);

Remaining tasks

1. Apply patch
2. ???
3. Profit!