launcher-gtk: set spin button to proper zoom level on startup
launcher-gtk: set spin button to proper zoom level on startup

StanciuMarius/Libchamplain-map-wrapping,potyl/champlain,potyl/champlain,potyl/champlain,GNOME/perl-Gtk2-Champlain,GNOME/perl-Champlain,Distrotech/libchamplain,potyl/champlain,GNOME/libchamplain,Distrotech/libchamplain,GNOME/perl-Gtk2-Champlain,PabloCastellano/libchamplain,StanciuMarius/Libchamplain-map-wrapping,StanciuMarius/Libchamplain-map-wrapping,GNOME/perl-Champlain,PabloCastellano/libchamplain,PabloCastellano/libchamplain,StanciuMarius/Libchamplain-map-wrapping,PabloCastellano/libchamplain,GNOME/libchamplain,StanciuMarius/Libchamplain-map-wrapping,Distrotech/libchamplain,PabloCastellano/libchamplain,Distrotech/libchamplain,Distrotech/libchamplain