added missing section_code columns to demo/training data

Needed demo data for showing off SSP, liquibase complained about section_code columns being null for the inserts.  Easiest thing I could figure to do was write a quick script to parse the XML and add the missing section code column for inserts that had formatted_course and section_number but no section_code.  Hopefully all of the demo data used the same format of formatted_course-section_number! This is the end result and it seems to work... liquibase ran happily anyway.  From what I remember, there were roughly 600 additions to demo_data and over 1000 for training.  If you want it and it doesn't mess up your migration scheme, great, if not, great.