pixbuf test failures on Rawhide

[Jeff Johnson]

+++ This bug was initially created as a clone of Bug #3257 +++

35 failures for desktop-t2c, a good number of them are:

/gdk-pixbuf-t2c/tests/GdkPixbufLoader_external/GdkPixbufLoader_external {1..3}
/gdk-pixbuf-t2c/tests/ModuleInterface_external/ModuleInterface_external {1..9}
/gdk-pixbuf-t2c/tests/FileSaving/FileSaving {29..34}

We've worked on this numerous times, and it works for a while, until someone
decides to move things again.

This is falling apart again on Rawhide:

cache file is:

/usr/lib/gdk-pixbuf-2.0/2.10.0/loaders.cache

which I *thought* was the same as it's been

I can see "checkboard" in /etc/gtk-2.0/gdk-pixbuf.loaders

Not sure what's falling apart now.