patch 7.4.1621

Problem:    Channel test doesn't work with Python 2.6.
Solution:   Add number in formatting placeholder. (Wiredool)

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1621,
 /**/
     1620,
 /**/