When escaping a string to be used as a sed regex, it is important
to only escape active characters. Escaping other characters is
undefined according to POSIX, and in practice leads to issues with
extensions such as GNU sed's \+.
Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>