mailinfo: allow stripping quoted CR without warning

mailinfo: allow stripping quoted CR without warning

In previous changes, we've turned on warning for quoted CR in base64 or
quoted-printable email messages. Some projects see those quoted CR a lot,
they know that it happens most of the time, and they find it's desirable
to always strip those CR.

Those projects in question usually fall back to use other tools to handle
patches when receive such patches.

Let's help those projects handle those patches by stripping those
excessive CR.

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>