Remove the definition of libpixbufloader_gdip_png_la_*
Remove the definition of libpixbufloader_gdip_png_la_*

libstatic-pixbufloader-gdip-png.la should not be built or at least not
included in STATIC_GDIPLUS_LIBS as we don't want to use the GDI+-based
loader for PNG, because if we do, we can't get (or was it set?) the
options of a PNG pixbuf that for instance some code in GIMP wants to do.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=607839

ahodesuka/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,jigpu/gtk,ahodesuka/gtk,simokivimaki/gtk,Adamovskiy/gtk,jigpu/gtk,davidt/gtk,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,Distrotech/gtk2,msteinert/gtk,jadahl/gtk,Adamovskiy/gtk,Lyude/gtk-,davidgumberg/gtk,ebassi/gtk,davidt/gtk,Lyude/gtk-,alexlarsson/gtk,grubersjoe/adwaita,jessevdk/gtk,alexlarsson/gtk,jigpu/gtk,ahodesuka/gtk,ebassi/gtk,grubersjoe/adwaita,ahodesuka/gtk,bratsche/gtk-,Distrotech/gtk2,Distrotech/gtk2,Lyude/gtk-,ebassi/gtk,Sidnioulz/SandboxGtk,jigpu/gtk,jessevdk/gtk,davidgumberg/gtk,jigpu/gtk,simokivimaki/gtk,bratsche/gtk-,jessevdk/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,Sidnioulz/SandboxGtk,simokivimaki/gtk,davidt/gtk,bratsche/gtk-,davidgumberg/gtk,davidgumberg/gtk,alexlarsson/gtk,davidgumberg/gtk,bratsche/gtk-,davidt/gtk,Lyude/gtk-,alexlarsson/gtk,ebassi/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,Adamovskiy/gtk,jadahl/gtk,davidt/gtk,ahodesuka/gtk,jadahl/gtk,Lyude/gtk-,jadahl/gtk,davidgumberg/gtk,grubersjoe/adwaita,chergert/gtk,msteinert/gtk,ebassi/gtk,jadahl/gtk,msteinert/gtk,jessevdk/gtk,jadahl/gtk,Lyude/gtk-,chergert/gtk,jessevdk/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,jigpu/gtk,msteinert/gtk,msteinert/gtk,ebassi/gtk,davidgumberg/gtk,Adamovskiy/gtk,Adamovskiy/gtk,Distrotech/gtk2,alexlarsson/gtk,ahodesuka/gtk,alexlarsson/gtk,chergert/gtk,bratsche/gtk-,simokivimaki/gtk,grubersjoe/adwaita,chergert/gtk,chergert/gtk,Adamovskiy/gtk,Lyude/gtk-,alexlarsson/gtk,Adamovskiy/gtk,msteinert/gtk,grubersjoe/adwaita,jadahl/gtk,davidt/gtk,simokivimaki/gtk,jadahl/gtk,jessevdk/gtk,Distrotech/gtk2,jigpu/gtk,chergert/gtk,jigpu/gtk,Distrotech/gtk2,grubersjoe/adwaita,chergert/gtk,simokivimaki/gtk