cache: call stream read with at least sector size space
Ensure we always pass a buffer of at least sector size to the read
function. This is never an issue with streams that have actual
sectors, as the reads will always return a multiple of sector size and
the cache is always used in blocks of sector size. However the rtp
protocol misuses this so it can just assume it always has a
sufficiently large buffer available and thus fails without this extra
hack.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@33120 b3059339-0415-0410-9bf9-f77b7e298cf2