Fix handling of DP reconnections
Fix handling of DP reconnections

Add a new handler for EventDPReconnected and factor out call to
valve.datapath_connect() to a separate method called by both event
handlers.

REANNZ/faucet,asmltd/faucet,REANNZ/faucet,shivarammysore/faucet,anarkiwi/faucet,Bairdo/faucet,mwutzke/faucet,shivarammysore/faucet,gwacter/faucet,faucetsdn/faucet,gizmoguy/faucet,asmltd/faucet,isomer/faucet,byllyfish/faucet,byllyfish/faucet,trungdtbk/faucet,gizmoguy/faucet,anarkiwi/faucet,wackerly/faucet,mwutzke/faucet,Bairdo/faucet,faucetsdn/faucet,gwacter/faucet,isomer/faucet,trungdtbk/faucet,trentindav/faucet,asmltd/faucet,asmltd/faucet,trentindav/faucet,wackerly/faucet,asmltd/faucet