[processing] allow other output formats than shapefile in GDAL

polygonize

(cherry picked from commit 8f291a9)

python/plugins/processing/algs/gdal/polygonize.py

@@ -53,11 +53,12 @@ def defineCharacteristics(self):
         self.addOutput(OutputVector(polygonize.OUTPUT, self.tr('Vectorized')))
 
     def getConsoleCommands(self):
+        output = self.getOutputValue(polygonize.OUTPUT)
+
         arguments = []
         arguments.append(self.getParameterValue(polygonize.INPUT))
         arguments.append('-f')
-        arguments.append('ESRI Shapefile')
-        output = self.getOutputValue(polygonize.OUTPUT)
+        arguments.append(GdalUtils.getVectorDriverFromFileName(output))
         arguments.append(output)
         arguments.append(QtCore.QFileInfo(output).baseName())
         arguments.append(self.getParameterValue(polygonize.FIELD))