Packages that need git as build-time or run-time dependency typically refer to
the attribute 'git', which is the expression with the least possible set of
features.
Users, however, who run "nix-env -i git", don't want that version, because it
lacks support for SVN, for sending e-mail, and it doesn't include the GUI. In
other words, users want gitFull by default, which is what this change
accomplishes.
svn path=/nixpkgs/trunk/; revision=27748