Update cms-tools-ana.xml

Assigned DOIs #89 and amended field 538 as per discussion with @pamfilos 
:+1: for using `538 $i` which seems to conform to [MARC 538 standard](http://www.loc.gov/marc/bibliographic/bd538.html).

However, since`538 $i` is new, we need to amend the data model. Note that `cms-tools-dimuon-filter.xml` and `cms-tools-ispy.xml` use this field differently.  Are you going to amend them as well?  

It would be good to make uniform treatment everywhere, in case we need to amend data model. See my past comments on making field-by-field changes rather than file-by-file changes: 

- https://github.com/cernopendata/opendata.cern.ch/pull/366#discussion_r18340441 
- https://github.com/cernopendata/opendata.cern.ch/pull/366#discussion_r18341025