improvements for "Git Access" page

[Filipp Gunbin]

Hi,

Some things which can be fixed:

- page url is https://www.gnupg.org/download/cvs_access.html , while
  it's certainly not "cvs" now.  Or was "vcs" meant?

- A little typo: "You must run ./autogen.sh before running the
  ./configure in the way suggested by the putput of autogen.sh."
                                          ^^^^^^

- libgpg-error seems to be hosted at
  git://git.gnupg.org/libgpg-error.git, but it's not mentioned in "Other
  Hosted Projects"

Thanks,
Filipp