Fix version bump for .10 release.

Makefile

@@ -84,7 +84,7 @@ bump-version: guard-VERSION
 	@echo "Update VERSION.txt to $(VERSION)"
 	# Work around sed being bad.
 	mv VERSION.txt VERSION.old
-	cat VERSION.old | sed s'/^[0-9]\.[0-9]\.[0-9].*/$(VERSION)/' > VERSION.txt
+	cat VERSION.old | sed s'/^[0-9]\.[0-9]*\.[0-9].*/$(VERSION)/' > VERSION.txt
 	rm VERSION.old
 	git add VERSION.txt
 	git commit -m "Update version number to $(VERSION)"