SystemMode in CPF overrides environment name in Git settings

[isc-pbarton]

I can use the "environment name" control in the Git settings page to set the system mode for the instance (DEVELOPMENT,TEST,LIVE). However if there is a SystemMode defined in the iris.cpf file, that will override the one we set when the instance restarts. We'll need to use Config.Startup to set it directly in the CPF (or document that system mode in CPF will override the one we set here).