Removed check variable type for CLI completions.

Found by Coverity (CID 1478003).
diff --git a/src/njs_builtin.c b/src/njs_builtin.c
index 5b03e72..eee44c6 100644
--- a/src/njs_builtin.c
+++ b/src/njs_builtin.c
@@ -639,7 +639,7 @@
     }
 
     var = ((njs_variable_node_t *) node)->variable;
-    value = njs_scope_valid_value(vm, var->index);
+    value = njs_scope_value(vm, var->index);
 
     if (!njs_is_object(value)) {
         return NULL;