force-leave not sufficient for EnsureRegistration failed with reserved node name

#### Overview of the Issue

I have a 3 node Consul cluster with Consul 1.9.4 revision 10bb6cb3b. All nodes come up, but one node (hostname: *consul-server-02*) is spawning EnsureRegistration warnings.

The [Hashicorp Consul-Errors-And-Warnings article](https://support.hashicorp.com/hc/en-us/articles/115015603408-Consul-Errors-And-Warnings) tells us we should just do a `consul force-leave consul-server-02` on one of the other live nodes and then rejoin.

Running force-leave and then restarting *consul-server-02* does not allow it to update the host-id for node name *consul-server-02*.

Expected behaviour: clean update of Consul Server 02 node name to new node-id.

#### Reproduction Steps

How to reproduce the current Consul Cluster state I'm not sure. I don't think I did anything utterly weird.

But at this point:

1. On *consul-server-02*: `consul agent -config-dir /etc/consul.d/ -retry-join 192.168.0.10`, resulting in WARN messages as shown below
2. On *consul-server-01*: `consul force-leave consul-server-02`
3. On *consul-server-02*: `consul agent -config-dir /etc/consul.d/ -retry-join 192.168.0.10`, still resulting in WARN messages as shown below

### Consul info for both Server 1 and Server 2

Server 1 info

```
agent:
check_monitors = 0
check_ttls = 0
checks = 0
services = 0
build:
prerelease =
revision = 10bb6cb3
version = 1.9.4
consul:
acl = disabled
bootstrap = false
known_datacenters = 1
leader = true
leader_addr = 192.168.0.10:8300
server = true
raft:
applied_index = 46001
commit_index = 46001
fsm_pending = 0
last_contact = 0
last_log_index = 46001
last_log_term = 52
last_snapshot_index = 32781
last_snapshot_term = 51
latest_configuration = [{Suffrage:Voter ID:44087325-f32d-acf4-34b5-45aa2ee5bbae Address:192.168.0.12:8300} {Suffrage:Voter ID:89927e54-0654-414f-f0d7-9546655e2f5c Address:192.168.0.10:8300} {Suffrage:Voter ID:598fc162-eab2-1d04-5bd9-9d360fad15c3 Address:192.168.0.11:8300}]
latest_configuration_index = 0
num_peers = 2
protocol_version = 3
protocol_version_max = 3
protocol_version_min = 0
snapshot_version_max = 1
snapshot_version_min = 0
state = Leader
term = 52
runtime:
arch = amd64
cpu_count = 2
goroutines = 322
max_procs = 2
os = linux
version = go1.15.8
serf_lan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 20
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 1047
members = 11
query_queue = 0
query_time = 1
serf_wan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 1
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 154
members = 3
query_queue = 0
query_time = 1
```

Server 2 info

```
agent:
check_monitors = 0
check_ttls = 0
checks = 0
services = 0
build:
prerelease =
revision = 10bb6cb3
version = 1.9.4
consul:
acl = disabled
bootstrap = false
known_datacenters = 1
leader = false
leader_addr = 192.168.0.10:8300
server = true
raft:
applied_index = 45988
commit_index = 45988
fsm_pending = 87
last_contact = 69.558881ms
last_log_index = 45988
last_log_term = 52
last_snapshot_index = 32785
last_snapshot_term = 51
latest_configuration = [{Suffrage:Voter ID:44087325-f32d-acf4-34b5-45aa2ee5bbae Address:192.168.0.12:8300} {Suffrage:Voter ID:89927e54-0654-414f-f0d7-9546655e2f5c Address:192.168.0.10:8300} {Suffrage:Nonvoter ID:598fc162-eab2-1d04-5bd9-9d360fad15c3 Address:192.168.0.11:8300}]
latest_configuration_index = 0
num_peers = 0
protocol_version = 3
protocol_version_max = 3
protocol_version_min = 0
snapshot_version_max = 1
snapshot_version_min = 0
state = Follower
term = 52
runtime:
arch = amd64
cpu_count = 2
goroutines = 84
max_procs = 2
os = linux
version = go1.15.8
serf_lan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 20
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 1047
members = 11
query_queue = 0
query_time = 1
serf_wan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 1
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 154
members = 3
query_queue = 0
query_time = 1
```

### Operating system and Environment details

OS: Ubuntu 20.04

```
$ uname -a
Linux consul-server-01 5.4.0-70-generic #78-Ubuntu SMP Fri Mar 19 13:29:52 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
```

### Log Fragments

This line starts spawning multiple times after start
```
2021-03-28T12:26:29.349Z [WARN] agent.fsm: EnsureRegistration failed: error="failed inserting node: Error while renaming Node ID: "598fc162-eab2-1d04-5bd9-9d360fad15c3": Node name consul-server-02 is reserved by node cdbe853e-fe92-5668-a995-2ebe091e0500 with name consul-server-02 (192.168.0.11)"
```

Start by reproducing the EnsureRegistration warning with the listed consul agent and force-leave commands on Consul 1.9.4, then trace the EnsureRegistration path and the node-renaming logic. Done means force-leave followed by restart and rejoin updates the host ID for consul-server-02 without repeated warnings.

Written by the indexing model from the issue text.