data tree BUGFIX allow duplicate instances in non-config leaf-lists

Instead of only state leaf-lists.
Fixes #1495
diff --git a/src/validation.c b/src/validation.c
index 9930f0c..209fb32 100644
--- a/src/validation.c
+++ b/src/validation.c
@@ -394,7 +394,7 @@
 
     switch (first->schema->nodetype) {
     case LYS_LEAFLIST:
-        if (!(first->schema->flags & LYS_CONFIG_R) && (first->schema->module->version >= LYS_VERSION_1_1)) {
+        if (!(first->schema->flags & LYS_CONFIG_W) && (first->schema->module->version >= LYS_VERSION_1_1)) {
             /* same values are allowed for non-configuration data */
             return 0;
         }