Respect the pulseaudio configuration from Qt.

It was previously ignored for Desktop Linux.

Change-Id: I214171d222a5e7e0ee64afde225a742adbda4adf
Task-number: QTBUG-43387
Reviewed-by: Andras Becsi <andras.becsi@theqtcompany.com>

src/core/config/desktop_linux.pri

@@ -14,3 +14,4 @@ GYP_CONFIG += \
     use_kerberos=0 \
     use_pango=0 \
 
+!contains(QT_CONFIG, pulseaudio): GYP_CONFIG += use_pulseaudio=0