Change MODS_Repository_Code heading in Music at Columbia

In the prepped remediated metadata, changed the element name
MODS_Repository_Code to item_-_MODS_-_RepositoryName_-_code
which is the name used in all previous remediated collections.
Regenerate MODS due to change in element name metadata.

The Music at Columbia remediated metadata used MODS_Repository_Code
instead of item_-_MODS_-_RepositoryName_-_code, which is was
used in all previous collection. Because of this, XSLT stylesheet
was not finding the repo code. Name was changed to usual name,
and the MODS was regenerated.