RFR 8185130: jlink should throw error if target image and current JDK versions don't match

[Sundararajan Athijegannathan]

Please review.

Bug: https://bugs.openjdk.java.net/browse/JDK-8185130
Webrev: http://cr.openjdk.java.net/~sundar/8185130/webrev.00/index.html

Thanks,
-Sundar