JMC-6461: Cleaner versioning information when not embedding a JDK

[Guru]

+1, Tested on Mac OS X. 

Thanks,
Guru
> On 08-May-2019, at 5:37 PM, Marcus Hirt <marcus at hirt.se> wrote:
> 
> Hi all,
> 
> Please review this change to clean up the about box versioning
> information when not embedding a JDK (seems to be the path that 
> most vendors have chosen).
> 
> Jira:   https://bugs.openjdk.java.net/browse/JMC-6461
> Webrev: http://cr.openjdk.java.net/~hirt/JMC-6461/webrev.0/
> 
> Kind regards,
> Marcus
>