analytics: reduce verbosity of log message in BusinessFactoryBase

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
payment: fix potential NPE in RefundProcessor

When the payment plugin wasn't found, RefundProcessor would throw an
NPE. This patch refactors and centralizes the calls to the plugin registry
to throw an appropriate exception in case the plugin is not found.

This also removes the unused method:

  PaymentPluginApi getPaymentProviderPlugin(String, InternalTenantContext)

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>