tdf#157288: "Primary key" missing when right click a field during table edition

Revert partly 0c2b2c9bab
"Use getXWeak in stoc"

Change-Id: I0344510dee33c8740937354d64c0e60115606d26
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/157178
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

stoc/source/proxy_factory/proxyfac.cxx

@@ -292,7 +292,8 @@ Any ProxyRoot::queryAggregation( Type const & rType )
             OSL_ASSERT( cpp_env != nullptr );
 
             // mind a new delegator, calculate current root:
-            Reference< XInterface > xRoot(getXWeak());
+            Reference< XInterface > xRoot(
+                static_cast< OWeakObject * >(this), UNO_QUERY_THROW );
             OUString oid;
             (*cpp_env->getObjectIdentifier)( cpp_env, &oid.pData, xRoot.get() );
             OSL_ASSERT( !oid.isEmpty() );