show: suppress extra newline when showing annotated tag

show: suppress extra newline when showing annotated tag

When showing a tag, our header parsing finishes with the
offset pointing to the newline separating the tag header
from the tag body. This means that the printed body will
always start with a newline.

However, we also add an extra newline when printing the
tagger information. This leads to an ugly double-newline:

    $ git show v1.6.3
    tag v1.6.3
    Tagger: Junio C Hamano <gitster@pobox.com>
    Date:   Wed May 6 18:16:47 2009 -0700

    GIT 1.6.3
    -----BEGIN PGP SIGNATURE-----
    ...

This patch removes the extra newline from the end of the
tagger headers. This is a better solution than suppressing
the separator newline, because it retains the behavior for
tags which have no tagger. E.g., "git show v0.99" will
continue to look like:

      $ git show v0.99
      tag v0.99

      Test-release for wider distribution.
      ...

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>