patman: separate emails in CC list with NULs

There is a contributor in Linux kernel with a comma in their name, which
confuses patman and results in invalid to- or cc- addresses on some
patches. To avoid this, let's use \0 as a separator when generating cc
file.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/func_test.py b/tools/patman/func_test.py
index 50a2741..2321f9e 100644
--- a/tools/patman/func_test.py
+++ b/tools/patman/func_test.py
@@ -198,9 +198,9 @@
         line += 4
         self.assertEqual(expected, tools.ToUnicode(lines[line]))
 
-        self.assertEqual(('%s %s, %s' % (args[0], rick, stefan)),
+        self.assertEqual(('%s %s\0%s' % (args[0], rick, stefan)),
                          tools.ToUnicode(cc_lines[0]))
-        self.assertEqual(('%s %s, %s, %s, %s' % (args[1], fred, ed, rick,
+        self.assertEqual(('%s %s\0%s\0%s\0%s' % (args[1], fred, ed, rick,
                                      stefan)), tools.ToUnicode(cc_lines[1]))
 
         expected = '''