send-email: work around double encoding of in-body From field.

git-send-email sends out the message taken from format-patch
output without quoting nor encoding.  When copying the From:
line to form in-body From: field, it should not copy it
verbatim, because the From: for the header is quoted according
to RFC 2047 when not ASCII.

The original came from Jürgen Rühle, but I moved the
string munging into a separate function so that later other
people can tweak it more easily.  Bugs introduced during the
translation are mine.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-send-email.perl

@@ -402,6 +402,15 @@ sub make_message_id
 $cc = "";
 $time = time - scalar $#files;
 
+sub unquote_rfc2047 {
+	local ($_) = @_;
+	if (s/=\?utf-8\?q\?(.*)\?=/$1/g) {
+		s/_/ /g;
+		s/=([0-9A-F]{2})/chr(hex($1))/eg;
+	}
+	return "$_ - unquoted";
+}
+
 sub send_message
 {
 	my @recipients = unique_email_list(@to);
@@ -555,6 +564,7 @@ sub send_message
 	}
 	close F;
 	if (defined $author_not_sender) {
+		$author_not_sender = unquote_rfc2047($author_not_sender);
 		$message = "From: $author_not_sender\n\n$message";
 	}