**- Why I did it**
As part of moving all SONiC code from Python 2 (no longer supported) to Python 3
**- How I did it**
- Convert enable_counters.py script to Python 3
- Reorganize imports per PEP8 standard
- Two blank lines precede functions per PEP8 standard
**- Why I did it**
We need RIF counters to be enabled by default. Flex Counter does probe for supported counters. If a platform does not support RIF counters, SAI will return NOT_SUPPORTED and Flex Counter will stop polling the counter.
**- How to verify it**
After fresh install rif counter gropup is enabled by default:
$ counterpoll show
Type Interval (in ms) Status
-------------------- ------------------ --------
QUEUE_STAT default (10000) enable
PORT_STAT default (1000) enable
RIF_STAT default (1000) enable
QUEUE_WATERMARK_STAT default (10000) enable
PG_WATERMARK_STAT default (10000) enable
Signed-off-by: Mykola Faryma <mykolaf@mellanox.com>
