Refacfored a more suitable ovs_redhat provider

  - Added a helper class/library to handle ifcfg content

  - Removed keep_ip and sleep parameters, replaced by
    automatic behaviour

  - No need for a redhat vs_bridge provider

  - Only port/bridge associated with a phyical interface get a
    ifcfg file managed

  - Requires Puppet 2.7.8+
    Not using optional_commands anymore

When the bridge is associated with an active physical interface
  - It will be initially populated from the existing interface
    file, inheriting its parameters

Change-Id: I584fb1442de9a760b3a092f96cbfcbcd6776fdba