git: actually use the remote parameter

When using the following sample, the provider does not use the value of remote
when cloning a repository:

```
vcsrepo {'/path/to/repo':
   ensure => 'present',
   provider => 'git',
   remote => 'test',
   source => 'git@somerepo:repo.git',
}
```

```
$ git remote
origin
```

This commit makes sure that the new repository has a remote with the
supplied value.

Closes #MODULES-430