##### SUMMARY

In devel branch, hostname module doesn't recognise Oracle Linux.

Regression from PR #56936 caused by PR #55459.

stable-2.8 branch is OK.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
hostname

##### ANSIBLE VERSION
```
2.9 / devel
```

##### CONFIGURATION

##### OS / ENVIRONMENT

```
$ head -n5 /etc/os-release
NAME="Oracle Linux Server"
VERSION="7.4"
ID="ol"
VERSION_ID="7.4"
PRETTY_NAME="Oracle Linux Server 7.4"
```

##### STEPS TO REPRODUCE
```yaml
 - name: set hostname
    hostname:
      name: "mytesthostname"
```

##### EXPECTED RESULTS
```
changed: [myhost]
```

##### ACTUAL RESULTS
```
fatal: [myhost]: FAILED! => {"changed": false, "msg": "hostname module cannot be used on platform Linux (Oracle)"}
```

##### ANALYSIS

This is a **regression** from PR #56936 caused by PR #55459.

Relevant lines from PR #56936:
[lib/ansible/modules/system/hostname.py#L660](https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/system/hostname.py#L660)
```
  class OracleLinuxHostname(Hostname):
      platform = 'Linux'
-     distribution = 'Oracle'
+     distribution = 'Ol'
      strategy_class = RedHatStrategy
```

But the update of bundled distro to 1.4.0 means that `Oracle` is now returned, not `Ol` (#55459):
[lib/ansible/module_utils/distro/_distro.py#L55](https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/distro/_distro.py#L55) 
```
- NORMALIZED_OS_ID = {
+ NORMALIZED_OS_ID = {
+     'ol': 'oracle',  # Oracle Enterprise Linux
+ }
```

This was not picked up in testing when #56936 was merged into devel because there is no automated testing against Oracle Linux.

**How to fix** - simply revert as shown:
[lib/ansible/modules/system/hostname.py#L660](https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/system/hostname.py#L660)
```
  class OracleLinuxHostname(Hostname):
      platform = 'Linux'
-     distribution = 'Ol'
+     distribution = 'Oracle'
      strategy_class = RedHatStrategy
```

**NB:** does not affect stable-2.8 because distro-1.4.0 is not included.
platform = 'Linux'
    distribution = 'Coreos'
    strategy_class = SystemdStrategy
class ScientificHostname(Hostname):
    platform = 'Linux'
    distribution = 'Scientific'
    strategy_class = RedHatStrategy
class OracleLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Ol'
    strategy_class = RedHatStrategy
class VirtuozzoLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Virtuozzo'
    strategy_class = RedHatStrategy
class AmazonLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Amazon'
    strategy_class = RedHatStrategy
class DebianHostname(Hostname):
    platform = 'Linux'
    distribution = 'Debian'
    strategy_class = DebianStrategy
class CumulusHostname(Hostname):
    platform = 'Linux'
    distribution = 'Cumulus-linux'
    strategy_class = DebianStrategy
class KaliHostname(Hostname):