* Fix some spelling error and add addition check in port_index_mapper.py script.
* Remove unneeded pyroute2 python module from sFlow container
Signed-off-by: Garrick He <garrick_he@dell.com>
**- Why I did it**
A memory issue was discovered during system test for scaling. The issue is documented here: https://docs.pyroute2.org/ipdb.html
> One of the major issues with IPDB is its memory footprint. It proved not to be suitable for environments with thousands of routes or neighbours. Being a design issue, it could not be fixed, so a new module was started, NDB, that aims to replace IPDB. IPDB is still more feature rich, but NDB is already more fast and stable.
**- How I did it**
- Rewrote the port_index_mapper.py script to use dB events.
- Convert to Python 3
