mailmap.c: remove unused function

map_email() is not used anywhere.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

mailmap.c

@@ -243,8 +243,3 @@ int map_user(struct string_list *map,
 	debug_mm("map_user:  --\n");
 	return 0;
 }
-
-int map_email(struct string_list *map, const char *email, char *name, int maxlen)
-{
-	return map_user(map, (char *)email, 0, name, maxlen);
-}

mailmap.h

@@ -4,7 +4,6 @@
 int read_mailmap(struct string_list *map, char **repo_abbrev);
 void clear_mailmap(struct string_list *map);
 
-int map_email(struct string_list *mailmap, const char *email, char *name, int maxlen);
 int map_user(struct string_list *mailmap,
 	     char *email, int maxlen_email, char *name, int maxlen_name);