t4203: demonstrate loss of single-character name in mailmap entry

A bug in mailmap.c:parse_name_and_email() causes it to overlook the
single-character name in "A <user@host>" and parse it only as
"<user@host>". Demonstrate this problem.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4203-mailmap.sh

@@ -247,6 +247,15 @@ test_expect_success 'cleanup after mailmap.blob tests' '
 	rm -f .mailmap
 '
 
+test_expect_failure 'single-character name' '
+	echo "     1	A <author@example.com>" >expect &&
+	echo "     1	nick1 <bugs@company.xx>" >>expect &&
+	echo "A <author@example.com>" >.mailmap &&
+	test_when_finished "rm .mailmap" &&
+	git shortlog -es HEAD >actual &&
+	test_cmp expect actual
+'
+
 # Extended mailmap configurations should give us the following output for shortlog
 cat >expect <<\EOF
 A U Thor <author@example.com> (1):