#214503 - Autoupdate does not recognize <content_description> in catalog.xml v. 2.7

http://netbeans.org/bugzilla/show_bug.cgi?id=214503

The parser of Autoupdate Catalog skips the 'content_description' 
element. It causes java.util.EmptyStackException in 
AutoupdateCatalogParser.endElement(AutoupdateCatalogParser.java:320). 
The simple fix adds reading this element.

Impact assessment: None

Risk assessment: It's very safe

The fix has been reviewed by Tomas Danek.

http://hg.netbeans.org/core-main/rev/82a616f25ff4

Thanks,
Jirka