patch 8.1.0622: adding quickfix items marks items as valid errors

Problem:    Adding quickfix items marks items as valid errors. (Daniel Hahler)
Solution:   Check when items are valid. (Yegappan Lakshmanan, closes #3683,
            closes #3633)

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    622,
 /**/
     621,
 /**/