Change some error return values to match AT-SPI-CORBA behavior
Change some error return values to match AT-SPI-CORBA behavior

gloob/gloob-s-at-spi2-core,GNOME/at-spi2-core,GNOME/at-spi2-core,gloob/gloob-s-at-spi2-core,gloob/gloob-s-at-spi2-core,GNOME/at-spi2-core