GStreamer: better camera device name logic.

Use the device ID for QCameraInfo::description() when the driver
doesn't provide any display name.

Change-Id: Iff1f17187ecb52262412f85db04d7108fae71717
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

src/gsttools/qgstutils.cpp

@@ -510,6 +510,8 @@ QVector<QGstUtils::CameraInfo> QGstUtils::enumerateCameras(GstElementFactory *fa
             } else {
                 driver = QByteArray((const char*)vcap.driver);
                 name = QString::fromUtf8((const char*)vcap.card);
+                if (name.isEmpty())
+                    name = entryInfo.fileName();
             }
             //qDebug() << "found camera: " << name;