patch 8.0.1439: if cscope fails a search Vim may hang

Problem:    If cscope fails a search Vim may hang.
Solution:   Bail out when a search error is encountered. (Safouane Baroudi,
            closes #2598)

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1439,
 /**/
     1438,
 /**/