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
Merge pull request #115 from instruct-br/use_remote_name_when_cloning_a_repo

git: actually use the remote parameter