Translation management search: avoid table with headers only

[andreas@…]

[jira2trac import : issue created on March 5, 2008 3:04:11 PM CET ​http://issues.cocoondev.org/browse/DSY-618 ]

How to reproduce:
Use a daisy instance where no documents have a reference language assigned yet.
Then go to "Tools - Translation management", you'll be presented the "Translation
management search". Perform a search with default parameters
(Show: Overview"), and you will get the table headers without any data
rows:

id branch name reference language de default en

This might confuse the user. Would be much better to have a message like: "No documents do have a
reference language assigned yet" or something similar instead of the table header row.