spice-pulse: compatibility with old pulse version
spice-pulse: compatibility with old pulse version

The commit 37ba949716ebf441110330 breaks compatibility with old versions
of libpulse as the volume and mute data in pa_source_output_info were
available only from version 1.0.0 onwards. Using other API function for
this which does not relay on audio per stream.

SPICE/spice-gtk,fgouget/spice-gtk,SPICE/spice-gtk,fgouget/spice-gtk,SPICE/spice-gtk,Fantu/spice-gtk,Fantu/spice-gtk,Fantu/spice-gtk,fgouget/spice-gtk,Fantu/spice-gtk,flexVDI/spice-gtk,SPICE/spice-gtk,flexVDI/spice-gtk