Suppress panic seen during undeployment of handlers

./testrunner -i /tmp/testexec.30193.ini get-cbcollect-info=True,GROUP=bucket_op -t eventing.eventing_rebalance.EventingRebalance.test_stop_start_eventing_rebalance,nodes_init=6,services_init=kv-kv-eventing-eventing-eventing-index:n1ql,dataset=default,groups=simple,reset_services=True,doc-per-day=10,GROUP=bucket_op

panic: runtime error: invalid memory address or nil pointer dereference

[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x708779]

goroutine 860 [running]:

panic(0x9db460, 0xc420016080)

        /home/couchbase/.cbdepscache/exploded/x86_64/go-1.7.3/go/src/runtime/panic.go:500 +0x1a1 fp=0xc422c905d0 sp=0xc422c90540

runtime.panicmem()

        /home/couchbase/.cbdepscache/exploded/x86_64/go-1.7.3/go/src/runtime/panic.go:62 +0x6d fp=0xc422c90600 sp=0xc422c905d0

runtime.sigpanic()

        /home/couchbase/.cbdepscache/exploded/x86_64/go-1.7.3/go/src/runtime/sigpanic_unix.go:24 +0x214 fp=0xc422c90658 sp=0xc422c90600

github.com/couchbase/eventing/dcp.Bucket.getConnPools(0x0, 0xc422e74e70, 0xc422e74eb8, 0xc4212be848, 0x4, 0xc4201d6090, 0x8, 0x9, 0x0, 0x0, ...)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/dcp/pools.go:188 +0x79 fp=0xc422c90688 sp=0xc422c90658

github.com/couchbase/eventing/dcp.(*DcpFeed).connectToNodes(0xc420282360, 0xc421c8c230, 0x1, 0x1, 0x42019abcd, 0xc420138600, 0x73, 0x10)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/dcp/upr.go:311 +0x24f fp=0xc422c90ac8 sp=0xc422c90688

github.com/couchbase/eventing/dcp.(*Bucket).StartDcpFeedOver(0xc420a16f00, 0xc421d865b0, 0x6e, 0x400000000, 0xc421c8c230, 0x1, 0x1, 0xabcd, 0xc420138600, 0x43c7908100000003, ...)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/dcp/upr.go:169 +0x4d2 fp=0xc422c90b98 sp=0xc422c90ac8

github.com/couchbase/eventing/consumer.glob..func16(0xc4222160c0, 0x4, 0x4, 0x10, 0x1)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/bucket_ops.go:407 +0x228 fp=0xc422c90db0 sp=0xc422c90b98

github.com/couchbase/eventing/util.Retry(0xf60100, 0xc421c8c1b8, 0xaef568, 0xc4222160c0, 0x4, 0x4, 0x0, 0x0)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/util/retry.go:64 +0x59 fp=0xc422c90e18 sp=0xc422c90db0

github.com/couchbase/eventing/consumer.(*Consumer).dcpRequestStreamHandle(0xc4207db000, 0xc42283036d, 0xc42283d540, 0x0, 0x9a3100, 0xc420ab5648)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/process_events.go:601 +0x1686 fp=0xc422c91348 sp=0xc422c90e18

github.com/couchbase/eventing/consumer.(*Consumer).updateVbOwnerAndStartDCPStream(0xc4207db000, 0xc422805e80, 0x3c, 0x36d, 0xc42283d540, 0x0, 0x0)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/vbucket_takeover.go:356 +0x561 fp=0xc422c919a0 sp=0xc422c91348

github.com/couchbase/eventing/consumer.(*Consumer).doVbTakeover(0xc4207db000, 0x9a036d, 0xc421c397d8, 0xc4202b9d4e)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/vbucket_takeover.go:318 +0x5b3 fp=0xc422c91d10 sp=0xc422c919a0

github.com/couchbase/eventing/consumer.glob..func1(0xc421b58440, 0x2, 0x2, 0x1, 0x1)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/bucket_ops.go:18 +0xbe fp=0xc422c91dd0 sp=0xc422c91d10

github.com/couchbase/eventing/util.Retry(0xf60100, 0xc421c397d0, 0xaef588, 0xc421b58440, 0x2, 0x2, 0xc421bb2000, 0x10000)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/util/retry.go:64 +0x59 fp=0xc422c91e38 sp=0xc422c91dd0

github.com/couchbase/eventing/consumer.(*Consumer).vbsStateUpdate.func1(0xc4207db000, 0x2, 0xc421b580c0, 0xc, 0x10, 0xc421c39790)

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/vbucket_takeover.go:230 +0x3a6 fp=0xc422c91f60 sp=0xc422c91e38

runtime.goexit()

        /home/couchbase/.cbdepscache/exploded/x86_64/go-1.7.3/go/src/runtime/asm_amd64.s:2086 +0x1 fp=0xc422c91f68 sp=0xc422c91f60

created by github.com/couchbase/eventing/consumer.(*Consumer).vbsStateUpdate

        /home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/eventing/consumer/vbucket_takeover.go:237 +0x932