date does not recognise ULAT timezone to calculate UTC date

[Jeff.Green]

Running the command date on our server in Mongolia gives

$ date
Wed Jun 19 18:13:14 ULAT 2013

However entering a date with the ULAT timezone to calculate the UTC date of an 
event in the past gives an error

$ date -u --date="25 May 2013 20:13 ULAT"
date: invalid date `25 May 2013 20:13 ULAT'

Using the same format (ie taking the local timezone from a date command) works 
on our servers in other timezones such as CET, CEST, or SGT works perfectly.




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