USB Creator fails to delete device

[Xwarman]

USB Creator fails reproducable if I try to delete an usb device.

Error Message:
org.freedesktop.DBus.Python.gi._glib.GError: Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
  File "/usr/share/usb-creator/usb-creator-helper", line 237, in Format
    part.call_set_type_sync('0x0c', no_options, None)
gi._glib.GError: GDBus.Error:org.freedesktop.UDisks2.Error.Failed: Error setting partition flags on /dev/sdi2: Command-line `sfdisk --change-id "/dev/sdi" 2 0x0c' exited with non-zero exit status 1:
WARNING: GPT (GUID Partition Table) detected on '/dev/sdi'! The util sfdisk doesn't support GPT. Use GNU Parted.

Use the --force flag to overrule this check.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: usb-creator-gtk 0.2.56.3ubuntu0.1
ProcVersionSignature: Ubuntu 3.16.0-37.51~14.04.1-generic 3.16.7-ckt9
Uname: Linux 3.16.0-37-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.10
Architecture: amd64
CurrentDesktop: Unity
Date: Tue May 19 10:35:39 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-05 (75 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
SourcePackage: usb-creator
UDisksDump: Error: [Errno 2] Datei oder Verzeichnis nicht gefunden: 'udisks'
UpgradeStatus: No upgrade log present (probably fresh install)

[Alberto Salvia Novella (es20490446e)]

Since this bug makes an application in main workable, it should have a priority of "high".