[BUG] Protect spdkClient in ReplicaCreate

[derekbit]

Describe the bug

Protect spdkClient in ReplicaCreate when replacing the client when there is a connection issue.

To Reproduce

Expected behavior

Support bundle for troubleshooting

Environment

• Longhorn version:
• Impacted volume (PV):
• Installation method (e.g. Rancher Catalog App/Helm/Kubectl):
• Kubernetes distro (e.g. RKE/K3s/EKS/OpenShift) and version:
  • Number of control plane nodes in the cluster:
  • Number of worker nodes in the cluster:
• Node config
  • OS type and version:
  • Kernel version:
  • CPU per node:
  • Memory per node:
  • Disk type (e.g. SSD/NVMe/HDD):
  • Network bandwidth between the nodes (Gbps):
• Underlying Infrastructure (e.g. on AWS/GCE, EKS/GKE, VMWare/KVM, Baremetal):
• Number of Longhorn volumes in the cluster:

Additional context

[longhorn-io-github-bot]

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  The reproduce steps/test steps are at:

It is not easy to trigger the error and the lock protection, so QA can simply validate the v2 volume attachment and detachment to see if there is any unexpected behavior.

• Does the PR include the explanation for the fix or the feature?

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  The PR is at

longhorn/longhorn-spdk-engine#104
longhorn/longhorn-instance-manager#379

• Which areas/issues this PR might have potential impacts on?
  Area: v2 volume
  Issues

[chriscchien]

Verified pass on longhorn master(longhorn-instance-manager 52decf), v1.6.x(longhorn-instance-manager c100da)

Below v2 volume operations worked well on master-head and v1.6.x-head

• Attach / detach
• Offline replica rebuilding
• Crash instance-manger pod when replica offline rebuilding, rebuild success.
• Create backup
• Restore the backup to v1 and v2 volume