RFR: JDK-8198303 - jdk11+1 was build with incorrect GA date as 2018-03-20

[Abhijit Saha]

It's a retroactive review request. Fix has been integrated after 
reviewed internally.

jdk11+1 (first build of jdk11) was promoted with incorrect Release Date. 
Need to be updated with correct GA date as per internal release roadmap.

Bug: https://bugs.openjdk.java.net/browse/JDK-8198303

Webrev: http://cr.openjdk.java.net/~asaha/8198303/webrev.01/


Thanks
Abhijit