Return "Unknown" when bearer type is unknown on Mac OS X.
Return "Unknown" when bearer type is unknown on Mac OS X.

tmcguire/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility,KDE/android-qt-mobility,enthought/qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,tmcguire/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,KDE/android-qt-mobility