MetadataExposure settings for dc.description.provenance are ignored/overridden by XMLUI templates

The DIM-Handler change made in DS-225 was made redundant by the full MetadataExposure patch introduced by DS-288. However, the DIM-Handler changes were never reverted, so even administrators cannot see provenance for items in simple item view / full item view. This applies to archived and workflow items.

The patch attached reverts DS-225.

This is such a simple and obvious change that I'll commit it to 1.7.1 (it's a bug) and 1.8.0 straight away, but I will bring the change up in the next dev meeting, so if anyone has any problems with it, we can revert the 1.7.1 commit.