shortening the git test suite

[Ricardo Wurmus]

Hi Guix,

git takes a very long time to build, because it has an extensive test
suite.  Most of the time is spent in running the SVN interoperability
tests, though, which are not really all that interesting for most uses
of git.

The Makefile says this:

  # Define NO_SVN_TESTS if you want to skip time-consuming SVN interoperability
  # tests.  These tests take up a significant amount of the total test time
  # but are not needed unless you plan to talk to SVN repos.

What do you think about disabling the SVN tests in the git package?

--
Ricardo