openonuAdapterGo: Panic during scale test

During the scale tests with voltha-2.10 at ADTRAN a panic occured in the openonu-go adapter. This is a consequential error due to permanently disrupted OMCI communication caused by problems with the communication path via the OLT. The go collection routines started by the metrics collector ignore the permanently disturbed OMCI communication and try to query the metrics again and again until a panic is finally triggered by access to the adapter's resources that are no longer available (see logs attached).