RFR: JDK-8080630 Stop doing sed manipulation of manifest files in SetupJavaCompilation

[Magnus Ihse Bursie]

We're currently breaking abstraction barriers by doing a sed replacement 
of $(RELEASE) and $(COMPANY_NAME) in SetupJavaCompilation. This 
replacement should be moved to a more proper place.

Unfortunately there were no shared dependencies between jrtfs-jar and 
demos, apart from buildtools. :( I tried adding it to the buildtools 
generation (which felt hackish anyway) but that broke since we include 
Tools.gmk multiple times which caused races with the generation of the 
manifest file. :-( We should probably do something about this (this will 
likely require a split of Tools.gmk into generation of tools and 
definition of command lines) but that was outside the scope for this 
fix, which is prompted by the version string changes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8080630
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8080630-no-sed-on-manifest/webrev.01

/Magnus