Autofoo cleanup for make dist/dictcheck

__Do not pull yet__ because make distcheck fails and I don't understand why. Please poke me on IRC when you have time to have a look and I'll add to this PR.

````bash
make[3]: Leaving directory `/home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_build/src'
make[3]: Entering directory `/home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_build'
python serializeimages.py 0.7.1 /home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_inst/share/applications < caja-dropbox.in > caja-dropbox
/bin/sh: caja-dropbox.in: No such file or directory
make[3]: *** [caja-dropbox] Error 1
make[3]: Leaving directory `/home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_build'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_build'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/home/sander/repos/caja-dropbox/caja-dropbox-0.7.1/_build'
make: *** [distcheck] Error 1
````