Verify the three custom MIB scalars at 1.3.6.1.4.1.8174.{1,2,3}.0 can be
read and written via SNMPv1.
Usage: python test_mib.py [device_ip] [read_community] [write_community]
Verify the read-only sensor table at 1.3.6.1.4.1.8174.20.* and the row-count
scalar at 1.3.6.1.4.1.8174.19.0.
The table has 8 rows x 8 columns = 64 leaves, plus the scalar. A SET on any
column must be rejected (notWritable), and re-walking the table after a delay
should show sensorTemperature / sensorReadCount / sensorUptime moving while
the polling task in the device's UserMain runs.
Usage: python test_mib.py [device_ip] [community]