Bug 927291 - Fix system has no response if sdcard is full during download. r=jduell

--HG--
extra : rebase_source : 7288b511e999050c1da1c2ed501aa3dc6ab1dba0
Bug 902587 - Part 2A: Refactor late-write-checks as client of IO Interposer r=BenWa

--HG--
rename : xpcom/build/mozPoisonWrite.h => xpcom/build/LateWriteChecks.h
rename : xpcom/build/mozPoisonWrite.h => xpcom/build/PoisonIOInterposer.h
rename : xpcom/build/mozPoisonWriteBase.cpp => xpcom/build/PoisonIOInterposerBase.cpp
rename : xpcom/build/mozPoisonWriteMac.cpp => xpcom/build/PoisonIOInterposerMac.cpp
rename : xpcom/build/mozPoisonWriteWin.cpp => xpcom/build/PoisonIOInterposerWin.cpp