Handle middle-of-the-page case without using a glue.
Using a glue may cause a spurious empty page if the multi-switch is at the end of the flow, with no satisfying way of fixing that.
Patch by Seifeddine Dridi


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/Temp_WhitespaceManagement@1582469 13f79535-47bb-0310-9956-ffa450edef68