Retrieve the filename from the log context and return it to the caller.
Call log_get_filename to retrieve the log file location. Call it anywhere after log_open.
This method allows the log file and its location to be displayed on the OpsConsole. The file and location are retrieved using the UAF agent property rap.service_logFile, which must be configured in agent-plugin.xml. It is unlikely that a custom feed handler would need to call log_get_filename.