Observed panic deleting cluster which was still initialising

[mdbooth]

/kind bug

I0906 15:54:43.919368     607 controller.go:114] "Observed a panic in reconciler: runtime error: invalid memory address or nil pointer dereference" controller="openstackmachine" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="OpenStackMachine" OpenStackMachine="default/mbooth-v1alpha6-md-0-s462m" namespace="default" name="mbooth-v1alpha6-md-0-s462m" reconcileID=e5573bc9-00ad-4385-8071-acd6c00596d1
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x1684519]

goroutine 247 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:115 +0x1e5
panic({0x1811400?, 0x2a89d40?})
	/usr/local/go/src/runtime/panic.go:914 +0x21f
sigs.k8s.io/cluster-api-provider-openstack/controllers.machineToInstanceSpec(0xc000e2e000, 0xc000e28000, 0xc0005a5900, {0x0, 0x0})
	/home/mbooth/src/kubernetes-sigs/cluster-api-provider-openstack/issue1606_v2/controllers/openstackmachine_controller.go:498 +0x699
sigs.k8s.io/cluster-api-provider-openstack/controllers.(*OpenStackMachineReconciler).reconcileDelete(0x1cf7e48?, {0x1cf9d60, 0xc000d0e9c0}, 0xc000aba820, 0xc000e2e000, 0xc000e28000, 0xc0005a5900)
	/home/mbooth/src/kubernetes-sigs/cluster-api-provider-openstack/issue1606_v2/controllers/openstackmachine_controller.go:276 +0x5b8
sigs.k8s.io/cluster-api-provider-openstack/controllers.(*OpenStackMachineReconciler).Reconcile(0xc00004e960, {0x1cf5870, 0xc0008c9800}, {{{0xc000b1f630?, 0x0?}, {0xc000dc12a0?, 0x410725?}}})
	/home/mbooth/src/kubernetes-sigs/cluster-api-provider-openstack/issue1606_v2/controllers/openstackmachine_controller.go:150 +0xa5f
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x1cf5870?, {0x1cf5870?, 0xc0008c9800?}, {{{0xc000b1f630?, 0x1753580?}, {0xc000dc12a0?, 0x1ce5978?}}})
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:118 +0xb7
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc00059e3c0, {0x1cf58a8, 0xc00001b090}, {0x189fee0?, 0xc000444920?})
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:314 +0x365
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc00059e3c0, {0x1cf58a8, 0xc00001b090})
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:265 +0x1c9
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:226 +0x79
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2 in goroutine 146
	/home/mbooth/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:222 +0x565
Exiting with code 2

Looks like we're referencing security groups before they're created without checking:

cluster-api-provider-openstack/controllers/openstackmachine_controller.go

Lines 495 to 500 in 8f00397

	if util.IsControlPlaneMachine(machine) {
	managedSecurityGroup = openStackCluster.Status.ControlPlaneSecurityGroup.ID
	} else {
	managedSecurityGroup = openStackCluster.Status.WorkerSecurityGroup.ID
	}

[mdbooth]

This might be a regression introduced by #1648.