patch 8.1.0617: NSIS installer gets two files from the wrong directory

Problem:    NSIS installer gets two files from the wrong directory.
Solution:   Change ${VIMRT} to "..\".
diff --git a/src/version.c b/src/version.c
index aadd161..77bfd81 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    617,
+/**/
     616,
 /**/
     615,