patch 7.4.1515

Problem:    Channel test is a bit flaky.
Solution:   Instead of a fixed sleep time wait until an expression evaluates
            to true.

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1515,
 /**/
     1514,
 /**/