[LyX/master] Set margins correctly for empty rows

[Jean-Marc Lasgouttes]

commit b4d85944a663821483de06b0b2eeae74973fa02a
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Sat Mar 5 13:50:28 2016 +0100

    Set margins correctly for empty rows
    
    Calling breakRow ensures that everything is set correctly.

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index f37e678..03467fa 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -478,7 +478,7 @@ bool TextMetrics::redoParagraph(pit_type const pit)
                        pm.rows().push_back(Row());
                Row & row = pm.rows()[row_index];
                row.pos(first);
-               row.endpos(first);
+               breakRow(row, right_margin, pit);
                setRowHeight(row, pit);
                row.setChanged(false);
                int const max_row_width = max(dim_.wid, row.width());