Disable media transfer protocol on android devices.

The only protocol we need enabled over USB is adb. Anything else is just a
potential source of problems.

BUG=

Review URL: https://codereview.chromium.org/294253004

git-svn-id: http://src.chromium.org/svn/trunk/src/build@273089 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/device_settings.py

@@ -35,6 +35,9 @@ def ConfigureContentSettingsDict(device, desired_settings):
     logging.error('Skipping content settings configuration due to outdated sdk')
     return
 
+  device.old_interface.system_properties['persist.sys.usb.config'] = 'adb'
+  device.old_interface.WaitForDevicePm()
+
   for table, key_value in sorted(desired_settings.iteritems()):
     settings = content_settings.ContentSettings(table, device)
     for key, value in key_value.iteritems():