Using the fo property last-line-end-indent instead of a hard coded value.

Using the fo property last-line-end-indent instead of a hard coded value.
This fixes item 1) in bug 36533.

Note that the old behaviour (before the changes) was not completely equivalent to the one requested by the specs, as the empty space was not necessarily placed at the end of the line; for example, the last line in a right-aligned paragraph was aligned as the previous lines, although shorter.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@279338 13f79535-47bb-0310-9956-ffa450edef68