mailmap: do not lose single-letter names

In parse_name_and_email() function, there is this line:

	*name = (nstart < nend ? nstart : NULL);

When the function is given a buffer "A <A@example.org> <old@x.z>",
nstart scans from the beginning of the buffer, skipping whitespaces
(there isn't any, so nstart points at the buffer), while nend starts
from one byte before the first '<' and skips whitespaces backwards
and stops at the first non-whitespace (i.e. it hits "A" at the
beginning of the buffer).  nstart == nend in this case for a
single-letter name, and an off-by-one error makes it fail to pick up
the name, which makes the entry equivalent to

	<A@example.org> <old@x.z>

without the name.

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

mailmap.c

@@ -122,7 +122,7 @@ static char *parse_name_and_email(char *buffer, char **name,
 	while (nend > nstart && isspace(*nend))
 		--nend;
 
-	*name = (nstart < nend ? nstart : NULL);
+	*name = (nstart <= nend ? nstart : NULL);
 	*email = left+1;
 	*(nend+1) = '\0';
 	*right++ = '\0';

t/t4203-mailmap.sh

@@ -247,7 +247,7 @@ test_expect_success 'cleanup after mailmap.blob tests' '
 	rm -f .mailmap
 '
 
-test_expect_failure 'single-character name' '
+test_expect_success 'single-character name' '
 	echo "     1	A <author@example.com>" >expect &&
 	echo "     1	nick1 <bugs@company.xx>" >>expect &&
 	echo "A <author@example.com>" >.mailmap &&