Unref GdkPixbufLoader
Unref GdkPixbufLoader

GdkPixbufLoader wasn't unreffed when the tile was successfully loaded.
This caused a _huge_ memory leak.

Signed-off-by: Jiří Techet <af18a4329e30c3b95edc4d3e647176d16d87c9c7@gmail.com>

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