format-patch: make newline after signature conditional
When we print an email signature, we print the divider
"-- \n", then the signature string, then two newlines.
Usually the signature is a one-liner (and the default is just the
git version), so the extra newline makes sense. But one could
easily specify a multi-line signature, like this:
git format-patch --signature='this is my long signature
it has multiple lines
' ...
and it may end with its own newline, in which case we do not have
to add yet another one.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>