RFR: JDK-8005924: Make it possible to set both --with-user-release-suffix and --with-build-number

[Erik Joelsson]

This patch changes the behavior of --with-build-number and 
--with-user-release-suffix. Previously, you could only set one or the 
other and setting build-number would override user-release-suffix. With 
this patch it's possible to set both. This simplifies nightly builds of 
various group forests where both a build counter and an arbitrary 
identifier need to be added to the version string.

http://cr.openjdk.java.net/~erikj/8005924/webrev.root.01/

/Erik