Remove the default timeout value
Remove the default timeout value

The timeout parameter now defaults to undef, and only takes effect
when given a truthy value (mostly, any non-negative integer value).

This has some advantages:
* we do not impose an arbitrary timeout value
* the factory default remains in effect unless explicitly overridden
* a global default from the user's manifest takes effect unless
  explicitly overridden

voxpupuli/puppet-download_file,puppet-community/puppet-download_file,voxpupuli/puppet-download_file,puppet-community/puppet-download_file