mailinfo: 'From:' header should be unfold as well

At present we do headers unfolding (see RFC822 3.1.1. LONG HEADER FIELDS) for
all fields except 'From' (always) and 'Subject' (when keep_subject is set)

Not unfolding 'From' is a bug -- see above-mentioned RFC link.

Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: navytux

builtin-mailinfo.c

@@ -871,6 +871,7 @@ static void handle_info(void)
 			}
 			output_header_lines(fout, "Subject", hdr);
 		} else if (!memcmp(header[i], "From", 4)) {
+			cleanup_space(hdr);
 			handle_from(hdr);
 			fprintf(fout, "Author: %s\n", name.buf);
 			fprintf(fout, "Email: %s\n", email.buf);

t/t5100/sample.mbox

@@ -2,7 +2,10 @@
 
 
 From nobody Mon Sep 17 00:00:00 2001
-From: A U Thor <a.u.thor@example.com>
+From: A
+      U
+      Thor
+      <a.u.thor@example.com>
 Date: Fri, 9 Jun 2006 00:44:16 -0700
 Subject: [PATCH] a commit.