Fuel cli show unreadable log in case of problem with yaml

[Vladimir Sharshov]

No way to understand, for example, that we should find problem in file "/etc/puppet/2015.1.0-8.0/modules/osnailyfacter/modular/swift/tasks.yaml", line 40, column 5 from trace below.

Trace:

```
[root@nailgun puppet]# fuel rel --sync-deployment-tasks --dir /etc/puppet
Traceback (most recent call last):
  File "/usr/bin/fuel", line 10, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/error.py", line 114, in wrapper
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/parser.py", line 266, in main
    parser.parse()
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/parser.py", line 143, in parse
    actions[parsed_params.action].action_func(parsed_params)
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/actions/base.py", line 62, in action_func
    method(params)
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/actions/base.py", line 110, in wrapped_f
    return f(self, params)
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/actions/release.py", line 154, in sync_deployment_tasks
    self.serializer.read_from_full_path(file_name))
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/serializers.py", line 109, in read_from_full_path
    return self.serializer["r"](file_to_read.read())
  File "/usr/lib/python2.7/site-packages/fuelclient/cli/serializers.py", line 37, in <lambda>
    "r": lambda d: yaml.load(d)
  File "/usr/lib64/python2.7/site-packages/yaml/__init__.py", line 71, in load
    return loader.get_single_data()
  File "/usr/lib64/python2.7/site-packages/yaml/constructor.py", line 37, in get_single_data
    node = self.get_single_node()
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 36, in get_single_node
    document = self.compose_document()
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 82, in compose_node
    node = self.compose_sequence_node(anchor)
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 111, in compose_sequence_node
    node.value.append(self.compose_node(node, index))
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 133, in compose_mapping_node
    item_value = self.compose_node(node, item_key)
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 82, in compose_node
    node = self.compose_sequence_node(anchor)
  File "/usr/lib64/python2.7/site-packages/yaml/composer.py", line 110, in compose_sequence_node
    while not self.check_event(SequenceEndEvent):
  File "/usr/lib64/python2.7/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
  File "/usr/lib64/python2.7/site-packages/yaml/parser.py", line 393, in parse_block_sequence_entry
    "expected <block end>, but found %r" % token.id, token.start_mark)
yaml.parser.ParserError: while parsing a block collection
  in "<string>", line 39, column 5:
        - name: (primary-)?swift
        ^
expected <block end>, but found '?'
  in "<string>", line 40, column 5:
        role: self
```

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/255150

[OpenStack Infra (hudson-openstack)]

Change abandoned by Fuel DevOps Robot (<email address hidden>) on branch: master
Review: https://review.openstack.org/255150
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.