LP#1721139 User Buckets - View Batch Changes date/time display not wrapping.

LP#1721139 User Buckets - View Batch Changes date/time display not wrapping.

This fixes a wrapping issue in Firefox for the date/time display in the 'View Batch Changes' modal in user buckets.  The css change was made to style.css.tt2 because the class can be used for other tables with text wrapping issues.

To test.
1. Using user buckets, make some batch changes on some patrons and roll back some of those changes.
2. Using Firefox, click on the 'View Batch Edits' button.
3. Apply patch.
4. Delete browser cache, and then log back in and 'View Batch Edits' again.

Signed-off-by: Garry Collum <gcollum@gmail.com>