NPE during EyeQL when review has null description

From FSH-6031.
NPE in the deprecated EyeQL implementation when doing a search like

https://crucible/api/rest/query?query=select%20revisions%20where%20csid%3D%27123%27%20return%20reviews&rep=MyRepo

if there is a review with a null description field.

This causes the JIRA-FishEye plugin to fail, as it currently uses that interface.