updated for version 7.3.519

Problem:    When completefunction returns it cannot indicate end of completion
            mode.
Solution:   Recognize completefunction returning -3.  (Mtsushita Shougo)

src/version.c

@@ -714,6 +714,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    519,
 /**/
     518,
 /**/