Improve ODF roundtrip of conditional formats. [part of #726201]

2014-03-12  Andreas J. Guelzow <aguelzow@pyrshep.ca>

	* openoffice-write.c (odf_write_style_cell_properties): write
	repeat-content only when it is defined
	* openoffice-read.c (odf_style_set_align_h): don't set the slignment
	if it isn't defined