Update en-GB.com_categories.ini

### How to reproduce

##### COM_CATEGORIES_NO_ITEM_SELECTED
1. Goto
administrator/index.php?option=com_categories&view=categories&extension=com_content
2. Make sure you have created at-least one category
3. Open google chrome (firefox, ...) console & run this Javascript code in console.
Joomla.submitbutton('categories.publish');
4. Form will be submitted, after submission it redirects to same view with following warning.
Warning
COM_CATEGORIES_NO_ITEM_SELECTED

#####

1. Goto
administrator/index.php?option=com_content&view=articles
2. Make sure you have created at-least one article
3. Open google chrome (firefox, ...) console & run this Javascript code in console.
Joomla.submitbutton('articles.publish');
4. Form will be submitted, after submission it redirects to same view with following warning.
Warning
COM_CONTENT_NO_ITEM_SELECTED

Apply patch and both strings are translated.

### Tracker
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=33201&start=0