make supervisor more resilient to missing .ser files

Currently supervisor process can not run without some kind of supervisor software like systemd. It exits too often on missing .ser file error with [INFO] Halting process

examples:

a)

2014-07-03 20:32:53 b.s.d.supervisor [INFO] Shutting down and clearing state for
id efd37b78-eb69-46a1-b317-9b5b4ba00584. Current supervisor time: 1404412373. S
tate: :timed-out, Heartbeat: #backtype.storm.daemon.common.WorkerHeartbeat{:time
-secs 1404412311, :storm-id "Storm-throughput-test-7-1404411531", :executors #

{[ 2 2] [4 4] [6 6] [-1 -1]}

, :port 6702}
2014-07-03 20:32:53 b.s.d.supervisor [INFO] Shutting down 55f2b426-c170-4e48-a76
8-2a82c0f383ce:efd37b78-eb69-46a1-b317-9b5b4ba00584
2014-07-03 20:32:54 b.s.d.supervisor [INFO] Removing code for storm id Storm-thr
oughput-test-7-1404411531
2014-07-03 20:32:55 b.s.d.supervisor [INFO] Shut down 55f2b426-c170-4e48-a768-2a
82c0f383ce:efd37b78-eb69-46a1-b317-9b5b4ba00584
2014-07-03 20:32:55 b.s.d.supervisor [INFO] Launching worker with assignment #ba
cktype.storm.daemon.supervisor.LocalAssignment{:storm-id "Storm-throughput-test-
7-1404411531", :executors ([6 6] [4 4] [2 2])} for this supervisor 55f2b426-c170
-4e48-a768-2a82c0f383ce on port 6702 with id 6518a348-1fea-4401-8b7b-365b4ac3627
9
2014-07-03 20:32:55 b.s.event [ERROR] Error when processing event
java.io.FileNotFoundException: File 'storm-local/supervisor/stormdist/Storm-thro
ughput-test-7-1404411531/stormconf.ser' does not exist

b)

2014-07-03 20:32:43 o.a.z.ClientCnxn [INFO] Socket connection established to localhost/127.0.0.1:2181, initiating session
2014-07-03 20:32:51 o.a.z.ClientCnxn [INFO] Unable to reconnect to ZooKeeper service, session 0x146fb27b8400027 has expired, closing socket connection
2014-07-03 20:32:51 o.a.c.f.s.ConnectionStateManager [INFO] State change: LOST
8d-1069-44e3-b3ca-c25390cbf719
2014-07-03 10:29:22 b.s.d.supervisor [INFO] Removing code for storm id Storm-throughput-test-1-140433
5149
2014-07-03 10:29:22 b.s.d.supervisor [INFO] Shut down 167cf900-2ec6-499b-9c09-12c1e48dbc08:f776588d-1
069-44e3-b3ca-c25390cbf719
2014-07-03 10:29:22 b.s.d.supervisor [INFO] Launching worker with assignment #backtype.storm.daemon.s
upervisor.LocalAssignment{:storm-id "Storm-throughput-test-1-1404335149", :executors ([3 3] [5 5] [4
4] [2 2] [1 1])} for this supervisor 167cf900-2ec6-499b-9c09-12c1e48dbc08 on port 6702 with id 1dd28a
8e-53cd-4af3-a4ae-7ebae0b9427f
2014-07-03 10:29:22 b.s.event [ERROR] Error when processing event
java.io.FileNotFoundException: File 'storm-local/supervisor/stormdist/Storm-throughput-test-1-1404335
149/stormconf.ser' does not exist

in both cases there were problems with zookeeper connection event failure before missing .ser file error.