Bugfix/vov 2806

Skip trying to pull a year out of the date_issued field to avoid problem with dates like "194u" which appear to parse to a relative date:

[2] pry(main)> DateTime.parse("194u")
=> Sun, 13 Jul 2014 00:00:00 +0000

We still probably want to coerce a year out of the date_issued field but need to think it through more.  @mbklein any ideas on how to do this?

While making this change I noticed duplicate and issues with cardinality of some solr fields and cleaned them up.  Due to these changes all MediaObjects will need to be reindexed.