Update base stage3 before build launch.

entrypoint.sh

@@ -5,6 +5,14 @@ die() {
     exit 1
 }
 
+# Get latest stage3 tag
+STAGE3_TAG=$(curl -s \
+    http://distfiles.gentoo.org/releases/amd64/autobuilds/latest-stage3-amd64.txt \
+    | grep -v "^#" | cut -d ' ' -f 1)
+
+# Download latest stable stage3 build
+wget -O /var/lib/catalyst/store/builds/stage3-amd64-latest.tar.xz \
+    http://distfiles.gentoo.org/releases/amd64/autobuilds/${STAGE3_TAG}
 
 # Download latest portage snapshot
 wget -O /var/lib/catalyst/store/snapshots/portage-latest.tar.bz2 \