Removed blacklist hack and added code to cleanup removable devices.

1. Now that we have the removable media model in the storage service
there is no need for the blacklist hack anymore since the invalid
file cleaner will not find files from unmounted devices anymore.

2. Whenever a removable device is mounted we now run the invalid file
resource cleaner on it in case any files were removed from the device
while it was not mounted with us.