patch 7.4.1520

Problem:    Channel test: Waiting for a file to appear doesn't work.
Solution:   In waitFor() ignore errors.

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1520,
 /**/
     1519,
 /**/