OpenOLT - Handle OLT down/restart case

python version of openoltadapter throws an exception when the OLT is down

20190318T174046.188 DEBUG MainThread kafka_proxy.send_message {topic: adapters.heartbeat, kafka_msg:

{"uptime": 1590.0032079219818, "ip": "172.30.0.6", "adapter": "openolt", "ts": 1552930846, "instance": "a53c3731b72c_1552929256", "type": "heartbeat"}

, event: sent-kafka-msg, instance_id: a53c3731b72c_1552929256, vcore_id: None}
20190318T174051.087 WARNING Thread-12 openolt_device.indications_thread {ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, error: <_Rendezvous of RPC that terminated with:
status = StatusCode.UNAVAILABLE
details = "Socket closed"
debug_error_string = "

{"created":"@1552930851.085679700","description":"Error received from peer","file":"src/core/lib/surface/call.cc","file_line":1017,"grpc_message":"Socket closed","grpc_status":14}

"
>, event: gRPC connection lost, instance_id: a53c3731b72c_1552929256, vcore_id: None}
20190318T174051.088 DEBUG MainThread openolt_device.do_state_down

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, event: do_state_down, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.088 DEBUG MainThread openolt_device.post_down

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, event: post_down, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.088 DEBUG MainThread openolt_device.do_state_init

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, positional_args: (u'192.168.1.114:50060',), event: grpc-host-port, instance_id: a53c3731b72c_1552929256, vcore_id: None}

Unhandled Error
Traceback (most recent call last):
File "/voltha/adapters/openolt/main.py", line 320, in start
self.start_reactor() # will not return except Keyboard interrupt
File "/voltha/adapters/openolt/main.py", line 430, in start_reactor
reactor.run()
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py", line 1261, in run
self.mainLoop()
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py", line 1270, in mainLoop
self.runUntilCurrent()
— <exception caught here> —
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py", line 869, in runUntilCurrent
f(*a, **kw)
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 382, in trigger
return self.machine._process(func)
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 1007, in _process
return trigger()
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 398, in _trigger
return self._process(event_data)
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 408, in _process
if trans.execute(event_data):
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 265, in execute
machine.callback(func, event_data)
File "/usr/local/lib/python2.7/dist-packages/transitions/core.py", line 988, in callback
func(event_data)
File "/voltha/adapters/openolt/openolt_device.py", line 370, in post_down
self.flow_mgr.reset_flows()
File "/voltha/adapters/openolt/openolt_flow_mgr.py", line 723, in reset_flows
self.flows_proxy.update('/', Flows())
exceptions.AttributeError: 'OpenOltFlowMgr' object has no attribute 'flows_proxy'

20190318T174051.092 INFO MainThread openolt_device.do_state_init

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, device_id: 4b208c2159de69416a8523f0, event: openolt-device-created, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.093 DEBUG MainThread openolt_device.post_init

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, event: post_init, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.094 DEBUG MainThread openolt_device.post_init

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, event: starting indications thread, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.095 DEBUG Thread-22 openolt_device.indications_thread

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, event: starting-indications-thread, instance_id: a53c3731b72c_1552929256, vcore_id: None}

20190318T174051.095 DEBUG Thread-22 openolt_device.indications_thread

{ip: 192.168.1.114:50060, id: 4b208c2159de69416a8523f0, device_id: 4b208c2159de69416a8523f0, event: connecting to olt, instance_id: a53c3731b72c_1552929256, vcore_id: None}