Fix dependency checks

[Emilio Pozuelo Monfort]

Hi,

depcheck.py does some dependency checks during the build process. The gnome-python-desktop check is wrong, it's checking for the presence of pygtksourceview2, but that's not in gnome-python-desktop, it comes from its own module and tarball releases (pygtksourceview).

I'm attaching a patch that does two things: move the check for pygtksourceview2 to its own check since scribes uses it, and fix the gnome-python-desktop to check for gnomeprint, which is a module from gnome-python-desktop that scribes uses.

[Mystilleef (mystilleef)]

Thanks! At some point I think we may need move these checks to autoconf.

[Mystilleef (mystilleef)]

Fixed in build 508.