meta-genivi-demo Audio Manager Pulse Audio Plugin patch

In order to get some context, please read this discussion (genivi-projects mailing list)

It is under discussion the option to move the plugin patch into its own repository, or develop the plugin to a state at which the maintainer would be willing to accept for upstream.

Until the discussion comes to an end and a proposal is made, GDP maintainers has decided to carry the patches to
enable the plugin to be built on later versions of Audio Manager.