schema tree CHANGE keep compiled identities on a single place

Instead of moving identities between lys_module and lysc_module, keep them
in lys_module structure and save some work and confusion which member is
used.
diff --git a/src/tree_schema_free.c b/src/tree_schema_free.c
index 2dadee5..1542fb0 100644
--- a/src/tree_schema_free.c
+++ b/src/tree_schema_free.c
@@ -830,8 +830,6 @@
     LY_CHECK_ARG_RET(NULL, module, );
     ctx = module->mod->ctx;
 
-    FREE_ARRAY(ctx, module->identities, lysc_ident_free);
-
     LY_LIST_FOR_SAFE(module->data, node_next, node) {
         lysc_node_free(ctx, node);
     }
@@ -864,7 +862,7 @@
 
     lysc_module_free(module->compiled, private_destructor);
     FREE_ARRAY(module->ctx, module->features, lysc_feature_free);
-    FREE_ARRAY(module->ctx, module->dis_identities, lysc_ident_free);
+    FREE_ARRAY(module->ctx, module->identities, lysc_ident_free);
     lysp_module_free(module->parsed);
 
     FREE_STRING(module->ctx, module->name);