Prevent from finalizing twice.

Prevent from finalizing twice.

If a develop calls provider_fini, and there is a connection with master,
the disconnected event callback will be called.

In that case, the developer can calls provider_fini again from the disconnected callback.
Then the finalizing sequence will be processed twice.

This can cause the serious problem of service providers.

So this patch will check the provider_fini calling status,
And prevent from finalizing twice.

Change-Id: I00b4efd3b52ad1de6a5dee2a40d30609e3ac318e