Merge pull request #6 from boxen/fix-build

fix broken specs
Don't crash when config is nil; Fixes #4

Without this early return, a nil `@resource[:config]` would raise
NoMethodError when friendly_config tried to iterate using `#each`.
Merge pull request #5 from dgoodlad/handle-nil-config

Don't crash when config is nil; Fixes #4
join the command into a string before executing

In a nutshell, `exec` blows up when you pass an array containing
elements with spaces in them. This can come up when giving the `extra`
arg:

```puppet
repository { "/tmp/repo":
  source  => "whatever/stuff",
  extra   => "-b my_cool_branch"
}
```

See boxen/puppet-ruby#19 for wayyyyy more detail.
Merge branch 'master' of git://github.com/boxen/puppet-repository
Merge branch 'fix-broken-repo-create' of git://github.com/boxen/puppet-repository