RFR: JDK-8048131 - Replace JC_DAAPI with JC_DIO in DIO Code

[Jen Dority]

issue: https://bugs.openjdk.java.net/browse/JDK-8048131
webrev: http://cr.openjdk.java.net/~jld/8048131/

Hi All,

Need a review for this changeset that renames a debug constant from 
JC_DAAPI to JC_DIO.

Thanks,
Jen