pull-cluster-api-provider-azure-e2e failed when collecting logs

[jsturtevant]

/kind bug
/kind flake

[Before submitting an issue, have you checked the Troubleshooting Guide?]

What steps did you take and what happened:
Test failed when collecting logs: https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-sigs_cluster-api-provider-azure/2193/pull-cluster-api-provider-azure-e2e/1507460088535715840

{ Panic /home/prow/go/src/sigs.k8s.io/cluster-api-provider-azure/test/e2e/azure_test.go:116
Test Panicked
/usr/local/go/src/runtime/panic.go:90

Panic: runtime error: index out of range [1] with length 1

Full stack:
sigs.k8s.io/cluster-api-provider-azure/test/e2e.AzureLogCollector.CollectMachinePoolLog({}, {0x25def80, 0xc0000560d0}, {0x2625038, 0xc0001ff110}, 0xc000259798, {0xc000bdb4a0, 0x57})
	/home/prow/go/src/sigs.k8s.io/cluster-api-provider-azure/test/e2e/azure_logcollector.go:105 +0x5df
sigs.k8s.io/cluster-api/test/framework.(*clusterProxy).CollectWorkloadClusterLogs(0xc000b448c0, {0x25def80, 0xc0000560d0}, {0xc000677970, 0xf}, {0xc000f2ec00, 0x14}, {0xc003e14270, 0x2d})
	/home/prow/go/pkg/mod/sigs.k8s.io/cluster-api/[email protected]/framework/cluster_proxy.go:251 +0x76a
sigs.k8s.io/cluster-api-provider-azure/test/e2e.(*AzureClusterProxy).CollectWorkloadClusterLogs(0xc000b35180, {0x25def80, 0xc0000560d0}, {0xc000677970, 0xf}, {0xc000f2ec00, 0x14}, {0xc003e14270, 0x2d})
	/home/prow/go/src/sigs.k8s.io/cluster-api-provider-azure/test/e2e/e2e_suite_test.go:130 +0x14b
sigs.k8s.io/cluster-api-provider-azure/test/e2e.dumpSpecResourcesAndCleanup({0x25def80, 0xc0000560d0}, {{0x22b776a, 0x17}, {0x262fbf0, 0xc000b35180}, {0xc000950180, 0xf}, 0xc000f5c420, 0xc0009f0350, ...})
	/home/prow/go/src/sigs.k8s.io/cluster-api-provider-azure/test/e2e/common.go:139 +0x204
sigs.k8s.io/cluster-api-provider-azure/test/e2e.glob..func1.2()
	/home/prow/go/src/sigs.k8s.io/cluster-api-provider-azure/test/e2e/azure_test.go:133 +0x285

What did you expect to happen:

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• cluster-api-provider-azure version:
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):

[shysank]

Seeing the same error in #1873
cc @sonasingh46