gnu: libgsf: Do not propagate gdk-pixbuf.

Propagating gdk-pixbuf rather than gdk-pixbuf+svg is dangerous as it clashes
with GTK+'s own gdk-pixbuf+svg propagation.

* gnu/packages/gnome.scm (libgsf)[propagated-inputs]{gdk-pixbuf}: Move to...
[inputs] ... here.

gnu/packages/gnome.scm

@@ -3264,11 +3264,11 @@ XML/CSS rendering engine.")
        ("perl" ,perl)
        ("perl-xml-parser" ,perl-xml-parser)))
     (inputs
-     `(("zlib" ,zlib)
+     `(("gdk-pixbuf" ,gdk-pixbuf)
+       ("zlib" ,zlib)
        ("bzip2" ,bzip2)))
     (propagated-inputs
-     `(("gdk-pixbuf" ,gdk-pixbuf)
-       ("glib" ,glib)
+     `(("glib" ,glib)
        ("libxml2" ,libxml2)))
     (home-page "https://www.gnome.org/projects/libgsf")
     (synopsis "GNOME's Structured File Library")