remove a lot of unnecessary errors

remove a lot of unnecessary errors

For example it doesn't make sense to return this error

 org.freedesktop.DeviceKit.Disks.Error.NotPartition

since the client is already able to check in advance if the given
object really is a partition. So trim the error list to only contain
errors that the client can't predict. This leaves us with

 DEVKIT_DISKS_ERROR_FAILED,
 DEVKIT_DISKS_ERROR_BUSY,
 DEVKIT_DISKS_ERROR_CANCELLED,
 DEVKIT_DISKS_ERROR_INHIBITED,
 DEVKIT_DISKS_ERROR_INVALID_OPTION,
 DEVKIT_DISKS_ERROR_NOT_SUPPORTED,
 DEVKIT_DISKS_ERROR_ATA_SMART_WOULD_WAKEUP,