Gstreamer: Do not assume that the list index is the same as the device id.
Gstreamer: Do not assume that the list index is the same as the device id.

Integrated KDE change 1027568 by cguthrie.

This commit fixes a bug that was highlighted when devices had been added/removed or the backend was reloaded.
The AudioDevice used to use a static counter to allocate itself a device id that was propigated through the Phonon API.
Code in the Backend invalidly assumed that the index in the list was the same as this id.
(cherry picked from commit cc6406d4971c5656fc4b3eb53f96058a9640c6f7)

pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk