RFR: 8046389: Add missing @since tag under javax.sql.**

[Henry Jen]

Hi,

Please review a trivial webrev that provides missing @since tag for 
elements under javax.sql,

javax.sql.CommonDataSource was extracted out since 1.6, methods have 
@since 1.4 tag because those methods existed in origins since then.

http://cr.openjdk.java.net/~henryjen/jdk9/8046389/0/webrev/

Cheers,
Henry