update pyloxi to floodlight/loxigen-artifacts@148e1f6c2c0be1e6de04b4a0aa3649558b9a235a

Pulls in the bsn_arp_idle extension.
controller: accept class in the poll exp_msg parameter

This allows us to poll for e.g. ofp.message.bsn_arp_idle instead of
ofp.OFPT_EXPERIMENTER.

The integer type argument is still supported.

Polling for any message is now deprecated.
controller: remove redundant log
controller: include repr(exp_msg) in exception
controller: clean up poll loop
Merge into master from pull request #102:
Support polling for specific message classes (https://github.com/floodlight/oftest/pull/102)