Adding Changeset To Review doesn't seem to work with repository using LightSVN plugin.

Steps to reproduce:

• Using curl to run the rest service. e.g add a changeset to review "CR-5"

  curl --data @addchangeset.txt -u user:user http://127.0.0.1:8060/rest-service/reviews-v1/CR-5/addChangeset -H "Content-Type:application/xml" 
  

• The content of "addchangeset.txt" look like this:

  <addChangeset>
  <repository>lightSVN</repository>
  <changesets>
  <changesetData>
  <id>9</id>
  </changesetData>
  </changesets>
  </addChangeset> 
  

• Error exception is thrown, see the attached debug log

This is not reproducible using the Fisheye repository.