jdk10 RFR for JDK-8167423: Incorrect implementation of JDK_Version::to_string OR proper return statement is missing OR proper comment is needed

[Shafi Ahmad]

Hi All,

Summary: Adding return value check and update index variable.  It's a very small change to single file. 

Webrev link: http://cr.openjdk.java.net/~shshahma/8167423/webrev.00/
bug link: https://bugs.openjdk.java.net/browse/JDK-8167423

Testing: jprt  and jtreg test.

Regards,
Shafi