tree data BUGFIX lyd_owner_module behavior now consistent

It is meant to return the owner module for both
data and opaque nodes. For node modules there
is a new function now.
diff --git a/src/parser_xml.c b/src/parser_xml.c
index a117825..d6de91d 100644
--- a/src/parser_xml.c
+++ b/src/parser_xml.c
@@ -1944,7 +1944,7 @@
         assert(parent);
 
         /* parse "input" */
-        rc = lydxml_envelope(lydctx->xmlctx, "input", lyd_owner_module(parent)->ns, 0, envp);
+        rc = lydxml_envelope(lydctx->xmlctx, "input", lyd_node_module(parent)->ns, 0, envp);
         if (rc == LY_ENOT) {
             LOGVAL(ctx, LYVE_DATA, "Missing RESTCONF \"input\" object or in incorrect namespace.");
         }
@@ -1957,7 +1957,7 @@
         assert(parent);
 
         /* parse "output" */
-        rc = lydxml_envelope(lydctx->xmlctx, "output", lyd_owner_module(parent)->ns, 0, envp);
+        rc = lydxml_envelope(lydctx->xmlctx, "output", lyd_node_module(parent)->ns, 0, envp);
         if (rc == LY_ENOT) {
             LOGVAL(ctx, LYVE_DATA, "Missing RESTCONF \"output\" object or in incorrect namespace.");
         }