hg: build-infra/jdk9/hotspot: Move patching of Xusage out of Dist.gmk.

[magnus.ihse.bursie at oracle.com]

Changeset: dbd1f6e8a718
Author:    ihse
Date:      2016-02-04 15:33 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/hotspot/rev/dbd1f6e8a718

Move patching of Xusage out of Dist.gmk.

! makefiles/Dist.gmk
! makefiles/gensrc/GenerateSources.gmk