Merge branch 'kd/mailinfo-quoted-string' into maint

An author name, that spelled a backslash-quoted double quote in the human readable part "My \"double quoted\" name", was not unquoted correctly while applying a patch from a piece of e-mail. * kd/mailinfo-quoted-string: mailinfo: unescape quoted-pair in header fields t5100-mailinfo: replace common path prefix with variable