Fix ODF pattern roundtrip issue. [#724898]

2014-02-21  Andreas J. Guelzow <aguelzow@pyrshep.ca>

	* openoffice-read.c (oo_style_prop_cell): read new foreign elements
	* openoffice-write.c (odf_write_style_cell_properties): write
	foreign elements to describe pattern cell background fills