Fix provider loading issue in other modules.

The module works stand alone, but when included in other modules for
spec testing it causes a dubious load error:

    Failure/Error: should include_class 'git'
    Puppet::Error:
    Could not autoload puppet/type/file_line: Could not autoload puppet/provider/file_line/ssh: no such file to load -- puppet_x/puppetlabs/transport

This should resolve the load issue in spec testing with no impact to
functionality.
Merge pull request #28 from nanliu/fix

Fix provider loading issue in other modules.