init: Initialize spi_global_app_data->desktop_name early
init: Initialize spi_global_app_data->desktop_name early

Now that registration is done lazily, we should make sure to initialize
desktop_name/path early.

Fixes #9

GNOME/at-spi2-core,GNOME/at-spi2-core,GNOME/at-spi2-atk,GNOME/at-spi2-core