Fix branch of stable juno

[Fix] SAHARA_BRANCH change master to stable/juno
Sahara don't work at stable/juno.

```
2014-11-26 08:10:22.602 ERROR sahara.utils.api [-] Request aborted with status code 500 and message 'Internal Server Error'
2014-11-26 08:10:22.602 ERROR sahara.utils.api [-] Traceback (most recent call last):
  File "/opt/stack/sahara/sahara/utils/api.py", line 89, in handler
    return func(**kwargs)
  File "/opt/stack/sahara/sahara/api/acl.py", line 46, in handler
    exc=exceptions.Forbidden)
  File "/opt/stack/sahara/sahara/openstack/common/policy.py", line 314, in enforce
    self.load_rules()
  File "/opt/stack/sahara/sahara/openstack/common/policy.py", line 241, in load_rules
    self.policy_path = self._get_policy_path(self.policy_file)
  File "/opt/stack/sahara/sahara/openstack/common/policy.py", line 287, in _get_policy_path
    raise cfg.ConfigFilesNotFoundError((path,))
ConfigFilesNotFoundError: Failed to read some config files: policy.json
```

Because SAHARA_BRANCH is master when DevStack branch is stable/juno.
I fix sahara branch master to stable/juno

[Fix] Add gettext package to horizon apt
I got fail log

```
2014-11-28 02:13:29.288 | HEAD is now at d9f336b Merge "Make status in instance details screen translatable" into stable/juno
2014-11-28 02:13:29.290 | + cd /opt/stack/horizon
2014-11-28 02:13:29.290 | + ./run_tests.sh -N --compilemessages
2014-11-28 02:13:29.613 | WARNING:root:No local_settings file found.
2014-11-28 02:13:29.744 | CommandError: Can't find msgfmt. Make sure you have GNU gettext tools 0.15 or newer installed.
2014-11-28 02:13:29.780 | + exit_trap
2014-11-28 02:13:29.780 | + local r=1
2014-11-28 02:13:29.781 | ++ jobs -p
2014-11-28 02:13:29.781 | + jobs=
2014-11-28 02:13:29.782 | + [[ -n '' ]]
2014-11-28 02:13:29.782 | + kill_spinner
2014-11-28 02:13:29.782 | + '[' '!' -z '' ']'
2014-11-28 02:13:29.782 | + [[ 1 -ne 0 ]]
2014-11-28 02:13:29.782 | + echo 'Error on exit'
2014-11-28 02:13:29.783 | Error on exit
2014-11-28 02:13:29.783 | + [[ -z /opt/stack/logs ]]
2014-11-28 02:13:29.783 | + /home/vagrant/devstack/tools/worlddump.py -d /opt/stack/logs
2014-11-28 02:13:29.819 | + exit 1
```

Horoizon needs gettext package
https://github.com/openstack/horizon/blob/master/doc/source/topics/install.rst

I add gettext package to apt.