Pull ubifs changes from Artem Bityutskiy:
 "Mostly fixes for the power cut emulation UBIFS mode, and only one
  functional change which fixes a return error code"

* tag 'upstream-3.13-rc1' of git://git.infradead.org/linux-ubifs:
  UBIFS: correct data corruption range
  UBIFS: fix return code
  UBIFS: remove unnecessary code in ubifs_garbage_collect