Remove the generated .desktop file
    
    With sugar-toolkit-gtk3, a .desktop file is generated in installing a
    Activity. The Icon and Path properties in the .desktop file contains
    BUILDROOT in the file path. Hence, the checks in
    /usr/lib/rpm/check-buildroot fails and ultimately the packing is failed.
    This .desktop file is not being used in sugar itself, thus won't affect
    the functionality of the Activity. Hence as a temporary resolution,
    removing the generated .desktop file.