patch 9.1.0662: filecopy() may return wrong value when readlink() fails

Problem:  filecopy() may return wrong value when readlink() fails.
Solution: Set ret to -1 so that 0 is returned when readlink() fails.
          (zeertzjq)

closes: #15438

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 460afa9..3a6faeb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    662,
+/**/
     661,
 /**/
     660,