Idea #1515: Allow repairing incorrectly removed USB Mass Storage Device (flash memory stick)

Currently the Ubuntu (and linux kernel) throw away the drive cache for USB memory stick immediately after the memory stick has been removed from the system even if the device was not correctly unmounted. This should be fixed.

Suggested behavior (requires changes to both kernel and GUI):
1) User has copied some files to USB memory stick
2) User removes USB memory stick from the Ubuntu system
3) Ubuntu pops up a dialog that says: "The system has not finished writing the data to the USB device [some label here]. Please, reconnect the device and wait until the process has completed. Data on the device may be corrupted unless the process is completed." with buttons "Retry" and "Discard data".

Pressing Retry (or just connecting the USB device) should proceed to write the drive cache to the device and display a dialog on the screen until done. Hitting the "Discard" button would throw away the drive cache for that device and the data is lost. Unless the user selects that the data should be discarded, the kernel should keep the data.