Implement the detection of USB Flash devices on IVI.

BUG=XWALK-2040

This patch implement the feature of detecting USB Flash devices on ivi, as well as getting its "capacity" and "isRemovable" attributes.
The old implementation in system_info_storage_desktop.cc and system_info_storage_tizen.cc could neither get the right usb info on tizen. So libudev is the only way to get this kind of info  as far as I know.
From the udev api, I tested every possible method, none of them could distinguish whether the device is internal or usb flash except for ``udev_device_get_sysattr_value (struct udev_device *udev_device, const char *sysattr)``, the ``capability`` sysattr and ``removable`` sysattr are the only flags to distinguish between internal device, sdcard and usb flash.