[flang] Fix bug flang-compiler/f18#579 while here

Original-commit: flang-compiler/f18@eefbcdcb54
Reviewed-on: https://github.com/flang-compiler/f18/pull/580
Tree-same-pre-rewrite: false

flang/lib/semantics/resolve-names.cc

@@ -1973,6 +1973,7 @@ void ModuleVisitor::BeginModule(const parser::Name &name, bool isSubmodule) {
   auto &details{symbol.get<ModuleDetails>()};
   PushScope(Scope::Kind::Module, &symbol);
   details.set_scope(&currScope());
+  defaultAccess_ = Attr::PUBLIC;
   prevAccessStmt_ = nullptr;
 }