patch 8.1.0602: DirChanged is also triggered when directory didn't change

Problem:    DirChanged is also triggered when the directory didn't change.
            (Daniel Hahler)
Solution:   Compare the current with the new directory. (closes #3697)
diff --git a/src/version.c b/src/version.c
index 5db1001..f9154cd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    602,
+/**/
     601,
 /**/
     600,