gs vs. gs-esp

[Matt Zimmerman]

We currently install plain gs in the desktop install.  It turns out, however
(see #5910) that some of the printer drivers we ship only work with gs-esp.
gs-esp is described as being more specialized for printing applications, and
since that is the primary purpose of gs in our desktop install, perhaps we
should switch to gs-esp.

It seems that cupsys used to depend on gs-esp, but it was downgraded to a
Recommends by the maintainer due to some arguments (see the changelog).

Both gs and gs-esp are free software.  I propose that we add gs-esp to the
Desktop seed, explicitly replacing gs (which is currently implicitly used by
germinate).

Comments?

-- 
 - mdz