fix the off-by-one errors in file_storage as well as a NULL conversion warning (typo)
fix the off-by-one errors in file_storage as well as a NULL conversion warning (typo)

aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent