needless shell=True in a subprocess.Popen call

Whilst there is no issue with the following use of subprocess.Popen with shell=True today there is no reason to use it with shell=True in this instance.

In softwareproperties/MirrorTest.py on line 29 (through to line 34) under the PingWorker the following code is found:

                   host = mirror.hostname

                    self.parent.report_action("Pinging %s..." % host)
                    commando = subprocess.Popen("ping -q -c 2 -W 1 -i 0.5 %s" % host,
                                                shell=True, stdout=subprocess.PIPE,
                                                stderr=subprocess.STDOUT).stdout

The code should be changed to something like the following:

                    commando = subprocess.Popen(["ping", "-q", "-c 2", "-W 1", "-i 0.5", host]
                                                , stdout=subprocess.PIPE,
                                                stderr=subprocess.STDOUT).stdout