Repository: ansible/ansible-lint

Issue:
include_tasks are skipped
# Issue Type
- Bug report

# Ansible and Ansible Lint details

```
ansible 2.6.3
  config file = None
  configured module search path = [u'/Users/PAvon1000248194/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/PAvon1000248194/.local/share/virtualenvs/20180822-kCpl1wg8/lib/python2.7/site-packages/ansible
  executable location = /Users/PAvon1000248194/.local/share/virtualenvs/20180822-kCpl1wg8/bin/ansible
  python version = 2.7.14 (default, Nov  2 2017, 16:04:18) [GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]
ansible-lint 3.4.23
```

- ansible installation method: pip
- ansible-lint installation method: pip

# Desired Behaviour

I want to have a rule for checking include_tasks tasks. However, they are removed from the task list at the moment.

# Actual Behaviour (Bug report only)

playbook.yml
```yaml
---
- hosts: localhost
  gather_facts: no
  tasks:
    - debug:
      msg: hello
    - include_tasks: tasks.yml
    - debug:
      msg: bye
```
tasks.yml
```yaml
---
- debug:
    msg: included task
```

output of `ansible-playbook playbook.yml`
```
PLAY [localhost] *****************************************

TASK [debug] *****************************************
ok: [localhost] => {
    "msg": "hello"
}

TASK [include_tasks] *****************************************
included: tasks.yml for localhost

TASK [debug] *****************************************
ok: [localhost] => {
    "msg": "included task"
}

TASK [debug] *****************************************
ok: [localhost] => {
    "msg": "bye"
}

PLAY RECAP *****************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0
```

rule.py (simple rule only to visualise the task list)
```python
from ansiblelint import AnsibleLintRule

class rule(AnsibleLintRule):
    id = 'rule'
    tags = []

    def matchtask(self, file, task):
        print task['action']['__ansible_module__']
```

output of `ansible-lint -r . playbook.yml`
```
debug
debug
debug
```

desired output of `ansible-lint -r . playbook.yml`
```
debug
include_tasks
debug
debug
``` 


Discussion:
Actually I want this too, because there are likely a few things that rules could catch related to the recent changes to import_tasks, include_tasks, etc.
I've labelled it needs_implementation in case anyone wishes to do this, but I'll try and take a look at it myself when I have some time
I thought i fixed that with #285 
It seems that the fix got lost with commit c03c3e8

Resolving patch:
diff --git a/lib/ansiblelint/utils.py b/lib/ansiblelint/utils.py
--- a/lib/ansiblelint/utils.py
+++ b/lib/ansiblelint/utils.py
@@ -85,7 +85,7 @@ def ansible_template(basedir, varname, templatevars, **kwargs):
 
 VALID_KEYS = [
     'name', 'action', 'when', 'async', 'poll', 'notify',
-    'first_available_file', 'include', 'import_playbook',
+    'first_available_file', 'include', 'include_tasks', 'import_tasks', 'import_playbook',
     'tags', 'register', 'ignore_errors', 'delegate_to',
     'local_action', 'transport', 'remote_user', 'sudo',
     'sudo_user', 'sudo_pass', 'when', 'connection', 'environment', 'args', 'always_run',


Test patch: