[2/3]Bluetooth: add "Accept all files" option for incoming files

 * Renamed some variable.
 * Re-organized the comment.
 * Reworded the commit message.

  This patch will make OBEX server respect the "accept all files"
  setting. If enabled, it will skip checking MIME type of incoming file,
  so the file types not present in whitelist can be accepted.
  Blacklist will be ignored as well. (There's nothing in blacklist in fact)
  If it's disabled, the check will be performed as usual.

Change-Id: I3904a25914d16d040126de43f5e6ed51993494c4