Registering a repository in a read-only jndi context should not generate an error

When a repository starts up, we attempt to register that repository in JNDI, either using a default or a configured JNDI name. If a NamingException is raised, we log that exception.

In the case of some web servers (e.g. Tomcat), the default global context is present but read-only.

For such cases, we shouldn't log an exception/error, we should only log an info/warn message.