patch 8.0.0869: job output is sometimes not displayed in a terminal

Problem:    Job output is sometimes not displayed in a terminal.
Solution:   Flush output before closing the channel.

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    869,
 /**/
     868,
 /**/